Five hundred and seventy-nine patients undergoing major laparotomy were randomly allocated to have midline or transverse incisions. Transverse incisions took longer to make and caused more bleeding but (in the absence of wound sepsis) no transverse wound burst and there were only 2 incisional hernias. In the midline group, without wound sepsis, there were 2 burst abdomens and 9 incisional hernias. When, however, those patients who suffered wound sepsis were also considered, there were no significant differences between the two groups.