This retrospective review of the case records was designed to determine the relationship between previous caesarean section and subsequent development of placenta praevia and placenta praevia with accreta. All women delivered with the diagnosis of placenta praevia at Princess Badeea Teaching Hospital from 1 January 1995 to 31 December 1996 were analysed. There were 18 651 deliveries in the study period. Sixty-five had placenta praevia, 21 of whom had a history of previous caesarean. The incidence of placenta praevia was significantly increased in those with a previous caesarean section (1.87%) compared with those with an unscarred uterus (0.25%) (P<0.0001). The risk increased as the number of previous caesarean sections increased. We also conclude that there is a high association between anterior placenta praevia, placenta accreta and previous caesarean section. This was enhanced with the increasing number of previous caesarean sections.