Purpose: To study the changes of telomerase activity and cytotoxic effects by Cisplatin; cis-dichlorodiamine platinum (CDDP) in cultured human choroidal melanoma. Material and Methods: The primary cultured human choroidal melanoma cells were cultured in the presence and absence of CDDP with different concentration and time respectively. The toxic effects were evaluated by MTT and the level of telormarse was detected by PCR-ELISA assay. And the relationship between telomerase activity and cytotoxic effects were analyzed by a correlation analysis.Results: Following the increase of the concentration and the time of CDDP, gradually repressed telomerase activity was detected in cultured cells. Meanwhile, the restrain rate of the cells increased. The telomerase activity at 24h and 1μg/ml was repressed significantly compared with the control cells. However, the appearance of cell death lagged behind the decreasing of telomerase.Conclusions: CDDP is an effective telomerase inhibitor in cultured choroidal melan Purpose: To study the changes of telomerase activity and cytotoxic effects by Cisplatin; cis-dichlorodiamine platinum (CDDP) in cultured human choroidal melanoma. Material and Methods: The primary cultured human choroidal melanoma cells were cultured in the presence and absence of CDDP with different The toxic effects were evaluated by MTT and the level of telormarse was detected by PCR-ELISA assay. And the relationship between telomerase activity and cytotoxic effects were analyzed by a correlation analysis. Results: Following the increase of the concentration and the time of CDDP, gradually repressed telomerase activity was detected in cultured cells. gradually, the restrain rate of the cells increased. The telomerase activity at 24h and 1 μg / ml was repressed significantly compared with the control cells. However, the appearance of cell death lagged behind the decreasing of telomerase. Conclusions: CDDP is an effective telomerase inhibitor in cultur ed choroidal melan