A train of the Lugano-Cadro-Dino line
Cadro is first mentioned in 735 as Cadelo. Under the Lombards kings, Cadro was mentioned in connection with the Totoniden from Campione d'Italia as a Vicus in 854. Some of the major landholders during the Middle Ages included the monastery of S. Ambrogio in Milan, the Benedictine monastery of S. Abbondio in Como and the Hospital of S. Maria in Lugano. The village of Dassone was originally part of Cadro, and was mentioned in 1591, but it was later abandoned, probably after a plague epidemic.
The village church of S. Agata was first mentioned in 1366. The rich stucco work is also from around that time. It was renovated in 1603 and again in the 20th Century. Until 1599, it was part of the parish of Sonvico. However, some of the houses in the village were part of the parish of Pazzalino-Pregassona. Cadro later became an independent parish, which, until 1801, also included Davesco-Soragno.
Agricultural income was supplemented by income sent home from emigrants. In 1911 Cadro was connected to the regional Lugano–Cadro–Dino railway. Since 1960, the population has tripled, and Cadro has become a municipality in the municipal agglomeration in Lugano.