The pathological findings in 29 hysterectomy specimens from a series of 175 patients undergoing trans-cervical resection of the endometrium are presented. In all but one case endometrium was present. Although all phases of the normal menstrual cycle were represented, in nine (28%) cases the endometrium appeared inactive, sometimes showing appearances similar to those in Asherman's syndrome. Adenomyosis was present in five (17%) cases and simple hyperplasia in one case. Haematocolpos was present in two cases. Inflammation was uncommon, usually mild in degree and present in the superficial myometrium. Four (14%) cases contained epithelioid or foreign body granulomas in the superficial myometrium. Deposits of haemosiderin and amorphous brown and/or particulate black pigment were seen in a total of 20 (69%) cases. A combination of transmission electronmicroscopy and energy dispersive analysis of X-rays showed these pigments to be a combination of charred organic material and metals, the latter corresponding to the composition of the diathermy cutting loop and electrocautery rollerball used in the ablative surgery.