Objective. To analyse changing trends of cesarean section (CS) birth rates over an 11 year period (2000–2010) using the Robson Ten Group Classification System (RTGCS) to identify the main contributors to the rising CS birth rates at a tertiary teaching hospital in Singapore. Design. Retrospective study. Setting. National University Hospital, Singapore. Population. All women who delivered between 1 January 2000 and 31 December 2010 (hospital maternity database). Methods. The RTGCS was used to classify these women according to parity, past obstetric history, singleton or multiple pregnancy, fetal presentation, gestational age and mode of onset of labor/delivery. Main outcome measures. The RTGCS results. Results. From 2000 to 2010 the CS rate increased from 19.9 to 29.6 per 100 births. Multiparous women with a previous cesarean birth (Group 5) were the greatest contributor to the CS rate, followed by nulliparous women with singleton cephalic full-term pregnancy in spontaneous labor (Group 1). These two groups contributed to 75% of the rise in the CS rate from 2000 to 2010. Conclusions. The increase in CS rate is attributed largely to the rising CS rate in Group 5, followed by Group 1. We propose that future efforts to reduce overall CS rate should be focused on increasing vaginal birth after cesarean and reduce CS rates in nulliparous women with singleton cephalic full-term pregnancy (Groups 1 and 2), which in turn will reduce the number of pregnant women with a previous CS.