Four human cell lines derived from cervical carcinomas (ME-180, SiHa, HT-3, and MS751) and three human cell lines derived from ovarian carcinomas (SK-OV-3, Caov-3, and NIH:OVCAR-3) were analyzed in vitro to determine the effect of recombinant interferon-gamma and recombinant human tumor necrosis factor-alpha on cell growth and survival. The effects of interferon-gamma, tumor necrosis factor-alpha, and both interferon-gamma and tumor necrosis factor-alpha on cell growth were measured after 24 and 72 hours of incubation by the incorporation of chromium 51. The results of this analysis showed that all seven cell lines were resistant to the antiproliferative action of tumor necrosis factor-alpha, that the growth of most cell lines was inhibited by interferon-gamma by 72 hours of incubation, and that after 72 hours of incubation all cell lines demonstrated a synergistic antiproliferative response to the combination of interferon-gamma and tumor necrosis factor-alpha. However, the effects of these cytokines on cell growth were found to differ among cell lines and varied with the concentration and the duration of incubation. The growth of one cell line (Caov-3) was stimulated by both tumor necrosis factor-alpha and interferon-gamma. These results suggest that the clinical effects of these cytokines on the growth of gynecologic cancers may be more complex than previously supposed.