The prevalence and determinants of primary caesarean section in Jamaica were estimated from a survey of women aged 14–49 years. Among 2328 women reporting 2395 live hospital births during the period January 1984 to May 1989, the prevalence of caesarean section was 4·1%. Repeat caesarean sections accounted for 1·3% of the hospital births during that period. Of the medical complications studied, prolonged labour and/or cephalopelvic disproportion carried the highest risks of primary caesarean section, followed by breech presentation, maternal diabetes, a high birth-weight baby, maternal hypertension, and a low birth-weight baby. The risk of primary caesarean section increased with maternal age, decreased with parity, was higher for urban than for rural residents, and was higher for births in private versus government hospitals.