The antitumor effects of human recombinant TNF (PAC-4D) were examined on three human gynecological carcinomas transplanted into CD-1 nude mice (uterine cervical carcinoma: UZ-1-N; ovarian carcinoma: OCl-1-N and OS-4-N). PAC-4D was administered intratumorally at a dose of 1,000 U, 3,000 U or 10,000 U/head from day 0 to day 4. Tumor size, body weight and peripheral WBC were measured on days 0, 4, 8, 12 and 16 and histological studies were made on day 6. The results were as follows: With UZ-1-N, intratumoral administration of PAC-4D at doses of 3,000 U and 10,000 U/head caused a marked inhibition of the tumor growth. Similarly, antitumor activity of PAC-4D against OCl-1-N was remarkable at a dose of 10,000 U/head. The administration of PAC-4D at doses of 3,000 U and 10,000 U/head was not effective against OS-4-N. The histological changes of grade II A-B by Ohboshi-Shimosato criteria of response were observed in the tumor of the effective groups against PAC-4D. There were no influences on the body weight and WBC after administration of PAC-4D. Although tumor cells possessed different sensitivities to PAC-4D, PAC-4D is strongly recommended for the treatment of gynecological malignancies.