During the years 1973-79, 704732 births took place in Sweden and 63 075 cesarean sections (CS) were performed. Within the study period there were 20 maternal deaths associated with delivery or puerperium. Thirteen of these patients were delivered by CS and 7 by the vaginal route. The hospital records of the 13 deaths associated with CS were closely analysed and it was found that 5 of the patients were critically ill before the beginning of surgery, and the CS per se was not responsible for these deaths. The 8 remaining maternal deaths gave a corrected (cesarean-attributed) maternal mortality rate of 12.7/100 000 cesarean deliveries. For vaginal deliveries the mortality rate was 1.1/100 000 deliveries. Thus, the risk of maternal death from CS in Sweden was twelve times as high as that from vaginal parturition. All maternal deaths except one, associated with CS, occurred after emergency operation. No deaths were ascribable to anesthesia complications. The most common causes of death after CS were pulmonary embolism, amniotic fluid embolism, coagulopathy and peritonitis. Time trends in the causes of maternal death in Sweden are discussed.