In a previous study of 500 nonpregnant women without cancer, including investigation of 45 biopsy specimens from cancer-free cervices, control values were obtained which will serve for comparison with the betaglucuronidase values obtained in our present work with cancer of the cervix. In the absence of neoplastic disease the vaginal fluid is subject to many factors which tend to influence beta-glucuronidase activity. Some of these are (a) methods of sampling,1(b) age of the patient,1(c) the menopause,1(d) hysterectomy,2(e) Trichomonas infections3and other types of vaginitis, (f) pregnancy,4(g) cyclic menstrual activity5and (h) presence of blood in the specimen. The present study is concerned mainly with an attempt to obtain additional insight into the significance of increased beta-glucuronidase levels in cancer of the cervix uteri, one of several instances in which malignant tissue has been found rich in this enzyme.