An assessment was made of the prophylactic effect of Endoxan and Bleomycin on 20-methylcholanthrene-induced cervical carcinoma in mice receiving the drugs from the early stage of experimental carcinogenesis. Marked inhibition of carcinomatous development and salient suppression of atypical epithelial proliferation were evident in animals treated with the anticancer chemotherapeutic agents. Administration of the drugs in early precancerous stage was observed to be more effective.