While many advances have been made in the chemotherapy of gynecologic cancers, treatment failures remain a major clinical problem. A growing understanding of the mechanisms of tumor cell resistance to antineoplastic drugs provides a framework for the development of chemotherapy regimens containing agents capable of modulating tumor response. Using a short-term ATP bioluminescence assay we studied the ability of two methylxanthines (caffeine, pentoxifylline) and an inhibitor of ADP-ribosyl transferase (3-aminobenzamide) to enhance cisplatin cytotoxicity in gynecologic cancer cell lines. Our findings of significantly enhanced cisplatin-induced cytotoxicity with two different analysis techniques confirms the effectiveness of these agents. These results may have future clinical significance.