Background and Aim: Trachyspermum copticum (L.) Link (called Zenian in Persian) is a native plant to Iran, Egypt, Afghanestan and India and it's aqueous and alcoholic extracts exert cytotoxic effects on human ovarian cancer cell cultures. Our aim was to study the Transforming Growth Factor-beta2 (TGF-beta2) levels in supernatant of human ovarian cell [A2780, sensitive and resistant to Cisplatin] cultures treated with aqueous and alcoholic, and essential oil of dried seeds ofTrachyspermum copticum (L.) Link.Materials and Methods: Human ovarian cancer cells (S and CP) treated with different concentrations (from 50 to 7000 μg/mL) of aqueous and alcoholic extracts. Using 3- (4, 5-dimethylthiazol-2-yl) -2, 5- diphenyl tetrazolium bromide test (MTT) and calculating cytotoxic percentage of each extracts after overnight incubation, non cytotoxic concentrations of extracts were selected.Non cytotoxic concentrations of aqueous extract for treatment of sensitive cells were 50, 100, 200, and 1000 μg/mL; and for resistant cells were 50, 100, 200, and 2000 μg/mL. Non cytotoxic concentrations of alcoholic extract for treatment of sensitive and resistant cells were 50, 100, and 200 μg/mL. Essential oil excluded from the study because of its extremely cytotoxic effects on cells even with very low concentrations.TGF-beta2 concentrations in supernatants were measured using enzyme-linked immunosorbent assay (ELISA). Results were analyzed with comparing mean test. P value less than 0.05 was considered statistically meaningful.Results: Treatment of sensitive cells with 200 μg/mL, and resistant cells with 50 and 2000 μg/mL of aqueous extract associated with very less concentrations of TGF-beta in supernatants comparing with other extract concentrations (p<0.001).But there was no meaningful association between the treatment of cells with alcoholic extract and TGF-beta2 concentrations in supernatants.Conclusion: Treatment of human ovarian cancer cells (A2780, sensitive and resistant to Cisplatin) with some concentrations of aqueous extract associated with diminished levels of TGF-beta2 in supernatants comparing other concentrations.Considering critical role of TGF-beta2 in growth and metastasis of tumor cells, further studies for determining the chemical components of aqueous extract and mechanism (s) of its effects on TGF-beta2 levels should be done.