Amylase activity was studied in 70 specimens of normal endometrium, 21 normal endocervices, 19 endometrial carcinomas, and 20 endocervical adenocarcinomas. Amylase was observed in the secretory (8.7 per cent) but not in the proliferative phase of the menstrual cycle. It is possible that the presence of amylase activity may serve a functional role in the degradation of glycogen to glucose in the secretory endometrium. The great majority (90.5 per cent) of uterine cervices showed strong and extensive staining of the endocervical glands for amylase. No glycogen was demonstrated and the role of amylase in endocervical glands remains obscure. Amylase was observed in one (5.3 per cent) out of 19 cases of endometrial carcinoma, and the presence of this enzyme may be considered a eutopic rather than an ectopic expression. Amylase was not detected in any of the endocervical adenocarcinomas examined. This study has shown a complete loss of amylase activity in malignant transformation of endocervical glands and this could be attributable to the immature nature of de-differentiated neoplastic cells.