The show began with only eleven main characters in its
first series, all of whom have since left the show. New main characters have been both written in and out of the series since, with a core of fifteen to twenty main actors employed on the serial at any given time. In casting the first series, Young sought out actors who were already well known in the television industry, something which has continued throughout the show's history, with cast members including
Alex Walkinshaw and
McHale was the show's lead writer for several years, and was the first British writer ever to become the "showrunner" of a major prime time drama. Under his tenure as executive producer, attempts were made at modernising the programme and appealing to a younger audience by taking on the
filmising technique and introducing musical montage segments into each episode. Seventeen complete series of Holby City have aired, and an eighteenth began airing in October 2015. The show has run for over 600-hour-long episodes. It is filmed in studios at the BBC Elstree Centre in Hertfordshire, with the 1960s office building Neptune House being used for multiple exteriors and interiors in the series. It has occasionally featured special episodes filmed on location abroad. From October 2010, Holby City moved to
high definition broadcasting.
In September 2016, as part of the broadcaster's Compete Or Compare Strategy, the BBC confirmed the show would be one of the first put up for tender.
 In the tender released in October, it was confirmed the contract, open to independent producers and
BBC Studios, would be for 3 series of a minimum 50 episodes per series, delivered from December 2017 with no break in transmission and produced from the existing production base at
BBC Elstree Centre.
 BBC Studios was announced as the winning bidder and will continue to produce the show through to 2020.
Holby City was created by
Tony McHale and
Mal Young as a spin-off from the BBC medical drama
Casualty, which is set in the
emergency department of the fictional Holby City Hospital.
 Young wanted to explore what happened to patients treated in Casualty once they were taken away to the hospital's surgical wards.
 While Casualty's scope is limited to "accident of the week" storylines about patients entering hospital, Holby City allowed the possibility of storylines about long-term care, rather than immediate life and death decisions.
 The series was commissioned by BBC One Controller
Peter Salmon, and began airing on
BBC One on 12 January 1999.
Richard Stokes believes that the series' popularity stems from the fact the hospital setting presents numerous plotline opportunities, explaining: "You have licence to create life-and-death situations every week, something you cannot do in any other set piece. The interaction of the characters can be sexy and social issues also permeate the writing. But, basically, hospital drama is successful because the viewers will forgive all the yukky bits for the wonder of a life saved."
 The focus of the series has developed since its conception, expanding to cover extra wards, including a
gynaecology ward, an
acute assessment unit and a
 When the maternity ward and a
special care baby unit were introduced during
series four, Young explained that new wards were necessary to allow the crew to rotate sets, maximising filming potential.
Episodes of Holby City cost around £370,000 to produce—more than the BBC soap opera
EastEnders, at £130,000 per episode, but less than Casualty at £450,000 per episode, or
Dalziel and Pascoe at £700–800,000 per episode. As Holby City is a high-volume, year-round production, it has relatively low production costs. Set-up costs can be spread over many years and standing sets can be repeatedly re-used, which is not the case for shorter series or one-off dramas.
The hospital set, at BBC Elstree Centre in Borehamwood.
Young remained an executive producer of Holby City until 2004, when he left the BBC to work for production company
 Former Casualty producer
Johnathan Young was an executive producer for the duration of Holby's first series, before joining
Channel 4 in 1999.
Kathleen Hutchison served alongside Mal Young as co-executive producer from 2003 to 2004, when she left the series to become executive producer of EastEnders.
 Hutchison was succeeded by former series producer Stokes,
 who remained working on Holby City until 2006, when McHale returned to the series.
 McHale was the first British writer ever to become the
showrunner of a major
prime time drama.
 He resigned from the position in 2009,
 and was succeeded by Belinda Campbell in 2010.
 In February 2011, it was announced that Johnathan Young would return to the BBC from March, succeeding Campbell as executive producer of both Casualty and Holby City.
Holby City storylines are planned eight months in advance.
 The series utilises a number of scriptwriters, who are found and scheduled by script development editor Simon Harper.
 Harper receives around 20 speculative scripts a week, and also finds writers through the BBC Writers Academy, a course established in 2005 which guarantees its graduates the opportunity to work on prime time television. McHale teaches at the academy, and graduate Abi Bown went on to become a regular writer for Holby City.
 Harper also recruits writers through the BBC's Continuing Drama Shadow Scheme, open to writers from all levels of experience.
 He believes that scripts which demonstrate synthesis between guest and serial storylines are "the spine of the show", and has stated that, "Good, cracking, intelligent, ballsy dialogue is a must," explaining: "It's about getting the characters' voices because the characters drive these shows. It is a love for and investment in these characters and the consistency of those characters." Harper does not require that writers are necessarily familiar with the show, and would like to attract more female scriptwriters.
McHale wrote the series' first episode, and served as the show's lead writer.
 His 2006 promotion to executive producer was part of a bid by Controller of BBC Drama Production
John Yorke to "put writers back at the heart of the process". Yorke called McHale's promotion "fantastic", explaining: "It means that for the first time you've got a writer running one of our big powerhouse BBC1 shows."
 Following McHale's resignation, his replacement as lead writer was Justin Young, who intends to introduce a more writer-led commissioning process from
series 13 onwards, with writers creating more of the theme and story of their episodes than was previously the case.
To ensure accuracy in scriptwriting, the serial employs a team of researchers to advise writers on nursing issues and health service politics.
 One medical advisor was given a cameo role in the series as an orthopaedic surgeon, and another, recovery nurse Rachel Carter, appears in Holby City as a scrub nurse.
 Another adviser, a
heart surgeon, has occasionally left
open-heart surgery to advise Holby City writers over the telephone.
 The programme utilises surgeons from different disciplines, who check scripts for accuracy. Carter believes this is particularly important in case viewers copy procedures they have seen in the show, such as
CPR. Series star
Amanda Mealing commented: "We pride ourselves on being realistic. You need to know what you are doing and why. It is a complex and foreign thing to act out an operation. For training, I watched a number of real ones."
 Cast members are taught how to give realistic injections, monitor blood pressure and check a pulse, and some are given the opportunity to observe procedures in real hospitals.
 Original cast member
George Irving observed
coronary artery bypass surgery performed at
Middlesex Hospital in preparation for his role as
Anton Meyer, while
Edward MacLiam observed
laparoscopic surgery being performed before joining the cast as Greg Douglas in
Filming and on-screen output
Holby City and Casualty are both set in Holby City Hospital, in the fictional county of Wyvern, in the southwest of England close to the Welsh border.
 The city exterior is represented by
Bristol, though Holby City is filmed at
BBC Elstree Centre in
 The Casualty set in Bristol was not large enough to encompass the surgical ward and operating theatre required for Holby City, and as a result, some crossover scenes in the first episode had to be shot twice, first on the Casualty set and then again at Elstree, with cast members travelling between the two locations.
 In October 2007, BBC cutbacks led
The Daily Telegraph to report that the Elstree site would be sold, and Holby City relocated to share a set with Casualty, possibly in
 In March 2009, the BBC confirmed that Casualty would move to a new set in Cardiff, however in the following month,
The Guardian announced that the BBC would retain Elstree Studios for at least another four years.
Several episodes of the series have been shot on location abroad. In 2004, the romance between nurse
Jess Griffin (
Verona Joseph) and anaesthetist
Zubin Khan (
Art Malik) culminated in an episode set in Paris.
 The following year, registrar
Diane Lloyd (
Patricia Potter) followed consultant
Ric Griffin (
Hugh Quarshie) to
Ghana as part of the BBC's "Africa lives" series, a week of programmes bringing an exploration of African culture to UK audiences.
 In 2006, an episode shot in
Switzerland featured consultant
Elliot Hope's (
Paul Bradley) wife Gina (
Gillian Bevan) committing
assisted suicide after her
motor neurone disease worsened.
 A 2007 episode filmed in
Dubai focussed on Holby registrars
Jac Naylor (
Rosie Marcel) and
Joseph Byrne (
Luke Roberts) meeting new nurse
Faye Morton (
Patsy Kensit), and in 2008, Joseph and consultant
Linden Cullen (
Duncan Pow) travelled to
Cape Town when Faye experienced difficulties there.
 Series producer Diana Kyle stated in November 2008 that due to major BBC budget cuts, the series would not be filming abroad again for the "foreseeable future".
 However, on 10 December 2012, it was announced that the show had filmed one episode in
Stockholm, which focusses on Jac tracking down hospital CEO
Henrik Hanssen (
Guy Henry) and exploring his backstory.
Holby City is shot using the
 Filming occurs from 8 am until 6 pm daily, 50 weeks a year.
 From July 2007 onwards, the show took on the
filmising technique, giving episodes the impression of having been shot on film. Kyle stated that this was intended to attract a younger audience and modernise the programme, and that there had been a "very positive" response to the change.
 On 28 May 2010, the BBC announced that it would be launching a
high definition (HD) simulcast of BBC One from the autumn, and that Holby City would move to HD by the end of the year.
 The series moved to HD broadcasting, with a
BBC HD simulcast, from the start of series 13 in October 2010.
eleventh series saw musical montage or "songtage" segments become standard in each episode, introduced by McHale as a means of modernising the show. Although McHale initially considered commissioning original pieces, budgetary constraints limited choices to pre-existing tracks. The use of songtages was first popularised by the US medical drama
Grey's Anatomy, however McHale stated he was unaware of this until Holby City had already adopted the technique.
 Music was generally selected by each episode's scriptwriter. If the writer was not specific about which songs should be used, the producers and director would select the music in post-production. Actors also have some input:
Hugh Quarshie personally selected the music he believed his character
Ric Griffin would listen to in theatre.
 Asked in June 2010 whether she felt songtages were appropriate for a serious drama show, Kyle responded: "Yes – sometimes. On a multi-strand series such as Holby, they are an excellent way of telling stories visually – a moment from each – to open or close an episode or create the passing of time in a concise way for the audience." Kris Green of entertainment and media website
Digital Spy suggested that the number of songs used per episode could be "very jarring", to which Kyle replied: "We plan to use music carefully in the future – maybe 'songtages', as above – and sourced music within a scene, that is music actually playing in the scene itself, for example on a radio – but less incidental."
Holby City premiered on 12 January 1999 on BBC One.
 Nineteen series of the show have since aired, and a twentieth began airing on 2 January 2018. The show's first series ran for nine episodes.
 In June 2000, then
Director-General of the BBC
Greg Dyke pledged extra funding for BBC One, some of which was used for extra episodes of Holby City.
 The second and third series ran for 16 and 30 episodes respectively, with new episodes then airing on a weekly basis from the fourth series onwards.
 Series four to nine and eleven all ran for 52 episodes, while series ten ran for 53 episodes, including the stand-alone finale episode "Mad World", set outside the hospital.
 All series from then on continued to consist of 52 episodes, with exception to the twelfth series, which consisted of 55 episodes in total. Young explained of the increase in series length: "Longer runs allow you to develop really strong storylines for the regular characters. As long as you do volume with passion, it'll work."
 The series reached its 500th episode on 13 April 2010.
Throughout Holby City's first series, episodes were 50 minutes long. From the second series onwards, episodes have been one hour in length.
 The show was originally broadcast on Tuesday nights at 8.10 pm, until a switch to Thursdays occurred for the second series, which began broadcasting in November 1999.
 Halfway through the third series in 2001, Holby reverted to its original Tuesday night slot, but now at 8.05 pm.
 Finally, the show moved into the 8 pm timeslot, where it has since remained.
 The show is occasionally broadcast on a different day dependent on BBC scheduling.
 In 2007, the show temporarily moved to Thursday nights, allowing HolbyBlue to air in the 8 pm Tuesday timeslot.
 BBC Scotland has for the most part broadcast the series at a later date mainly at 10.40, with its slot at 8pm filled with River city,