Four hundred eighty-five cases of histologically proven adenomyosis were reviewed to determine if that condition might have been induced by transplanted endometrium at the time of cesarean section. The rate of cesarean section in the study group was 6.4%. Evidence of the cesarean scar was noted histologically in 13 of 31 patients (42%) who had undergone cesarean section, and 2 of the 13 (15%) had evidence of glands and stroma within the scar. Both patients had other pathology that could account for their symptoms. Prior cesarean section does not appear to be a risk factor for symptomatic adenomyosis.