The Caesarean section rate has been rising in Australia in recent years. This study compares Caesarean section rates and indications for Caesarean section in 2 separate 2-year periods, 1970-71 and 1980-81, in a Sydney teaching hospital. The Caesarean section rate increased from 6.4% to 16.2% in this decade. Dystocia is now the most frequent indication for Caesarean section and accounted for 33.2% of the increase in rate while fetal distress contributed 23.8% of that increase. Repeat Caesarean section and breech presentation contributed 16.9% and 13.3% of the increase respectively. Caesarean section rates for all birthweights increased, but particularly in the very small infant and those above 3,500 g. Caesarean sections for public patients rose from 3.4% to 9.3% while for private patients the rate increased from 12.0% to 20.7%. While there has been some convergence of rates for public and private patients during the decade, private patients were still twice as likely to have a Caesarean section in 1980-81. The contribution of dystocia, as an indication for Caesarean section, to the increase in the rate over this period is consistent with recent international experience and indicates a strong trend towards procedural intervention.