The co-operative effects of recombinant human tumor necrosis factor (rH-TNF) and CPT-11, a new derivative of camptothecin, against the proliferation of human gynecologic tumor cell lines were examined in vitro. The lshikawa cells were responsive to rH-TNF, the HHUA cells exhibited a minimal degree of responsiveness to rH-TNF, and the HeLa S3 and Caov-3 cells were unresponsive to rH-TNF. The HHUA, Ishikawa and Caov-3 cells were responsive to CPT-11, and the HeLa S3 cells were relatively sensitive to CPT-11 cytotoxicity. In all four cell lines, rH-TNF at clinically achievable concentrations exhibited synergy with CPT-11. The combination therapy of rH-TNF and CPT-11 will be a new approach against gynecologic cancers.