The authors report a study they have made of 7,216 case histories designed to show the type and the number of the various maternal complications of the caesarean operation and compare these results with those found in the literature and those that occur after vaginal delivery. The maternal mortality rate directly associated with the operation is 1.38/000, which is between 5 and 25 times greater than those for vaginal delivery. The pre-operative anaesthetic and surgical complications are rare and are usually not very serious. They depend on the experience of the operators. The post-operative complications tend to be mainly due to infections and thrombo-embolic phenomena. If the most minor infections are included, the infection rate for caesarean operations rises to 20.6%, whereas thrombo-embolic complications are rare at 0.52%.