The effect of appendicectomy on the subsequent development of right inguinal hernia was investigated in 583 patients with hernias, 42 of whom had previously had appendicectomies. The incidence of right sided hernias was no greater among these patients than among those who had not had their appendixes removed. Neither sex was more prone to develop an inguinal hernia after appendicectomy, and no type of hernia (direct or indirect) predominated. The cause of right sided inguinal herniation after appendicectomy has been thought to be damage to the nerve supply of the inguinal muscles during the appendicectomy incision. All our 42 cases except two had had their appendicectomies through classic McBurney incisions, which were some distance away from the most common areas of nerve damage. We conclude that development of a right inguinal hernia is an unlikely complication of appendicectomy if a classic McBurney incision was used.