We have analysed in retrospect the incidence of cesarean section during the years 1977-1989 in the 1st Obstetric and Gynecologic Clinic of the University of Bologna, and the development over time of the principal indications. The average incidence (17.1%) of cesarean section increased progressively from 9% in 1977 to 28% in 1989 with a peak at the beginning of the '80s (the period during which cardiotocographic monitoring became routinely used). With regard to the indications from 1977 up to date cesarean sections carried out on account of fetal distress increased almost five-fold. The increase in cesarean sections carried out on account of maternal disease, breech presentation and previous cesarean section was less important, while those performed for dystocia resulted markedly reduced.