Objective To investigate the role of extracellular regulated kinase （ERK1/2） pathway in cisplatin-induced apoptosis in human ovarian carcinoma cells. Methods Cisplatin-induced apoptosis were stained with DAPI and was assessed microscopically in human epithelial adenocarcinoma ovarian cell line SKOV3 cells. ERK activation was determined by Western blotting using an anti-phospho-ERK antibody to detect ERK activity. The effect of PD98059 on ERK activity induced by cisplatin was detected by MTT assay. Results Marked apoptosis of SKOV3 cells resulted from 48 hours treatment with 20 μg/mL cisplatin. Strong activation of ERK was led to by 15 μg/mL cisplatin. Dose response and time course of cisplatin induced apoptosis in SKOV3 cells. Cisplatin-induced ERK activation occurred at 12 hours and increased to highest induction at 24 hours by Western blotting. The effect of PD 98059 on ERK activity induced by cisplatin at the concentration of 100 μmol/L PD 98059. Statistically significant decreased in cell survival were observed with 100 μmol/L PD 98059 at 15 and 20 μg/mL cisplatin （P< 0.05）. Conclusions Cisplatin activates the ERK signaling pathway in ovarian cancer cell line SKOV3. Inhibition of ERK acti-vity enhances sensitivity to cisplatin cytotoxity in ovarian cancer cell line SKOV3. Evaluation of ERK activity could be useful in predicting which ovarian cancer will response most favorably to cisplatin therapy.