Uterine adenomyosis is a common, almost banal, lesion, since it is found in one uterus out of three by careful histological examination. In a continuous series of 926 hysterectomies for various indications, 246 adenomyosis lesions were demonstrated. In only 65 cases, adenomyosis was the sole histological lesion explaining bleeding or pain, symptoms refractory to routine conservative treatment (haemostatic curettage and/or hormone treatment) and therefore justifying surgical removal of the uterus. The role of adenomyosis in the failure of conservative treatment for diffuse fibromatosis at around the age of the menopause must be remembered. Almost 50% of specimens of hysterectomy for fibroma show evidence of associated histological lesions of internal uterine endometriosis. Whilst the hysterographic diagnosis may be suspected in almost 2/3 of cases, direct appearances of adenomyosis are found in only one case in four.