Objective: To study the inhibitory effect of tirapazamine (TPZ) combined with LY294002, an inhibitor of phosphatidylinositol 3-kinase (P13K), on the growth of human ovarian carcinoma cells. Methods: Human ovarian carcinoma cells of the line H08910PM were cultured and treated with tirapazamine alone and treated with TPZ of different concentrations combined with LY294002 of the concentration of 50 μmol/L respectively under aerobic and hypoxic conditions. And human ovarian carcinoma cells of the line OVCAR-3 were cultured and treated with YPZ alone and treated with TPZ of different concentrations combined with LY294002 of the concentration of 25 μmol/L respectively under aerobic and hypoxic conditions. MTT method was used to detect the surviving fractions of these carcinoma cells. Results: The IC50 values of TPZ on the H08910PM cells under hypoxic condition was 40.6 μmol/L, significantly lower than that under aerobic condition (53.0 μmol/L, P < 0.01). The IC50 values of TPZ on the OVCAR-3 cells under hypoxic condition was 65.9 μmol/L, significantly lower than that under aerobic condition (97.4 μmol/L, P < 0. 01 ). The IC50 value of TPZ combined with LY294002 on the HP8910PM cells under hypoxic condition was 22.7 μmol/L, significantly lower than that under aerobic condition (31.5 μmol/L, P < 0.01). The IC50 value of TPZ combined with LY294002 on the OVCAR-3 cells under hypoxic condition was 49.1 μmol/L, not significantly different from that under aerobic condition (51.0 μmol/L, P > 0.05). Conclusion: TPZ inhibits the growth of human ovarian carcinoma cells. The inhibitory effects of TPZ on the growth of human ovarian carcinoma cell of the lines H08910PM and OVCAR-3 under hypoxic conditions are significantly higher than those under aerobic condition. LY294002 increases the inhibitory effect of TPZ on the ovarian cancer cells, compared with TPZ treatment alone, TPZ combined with LY294002 decreases the IC50 of H08910PM and OVCAR-3 cells significantly.