Abstract: The aim of this experiment was to find the appropriate dosage at which Testosterone Propionate (TP) is genotoxic enough to cause significant chromosome damage. TP was examined at 10, 20 and 40 μM, respectively and found to be significantly genotoxic at 20 and 40 μM, only in the presence of metabolic activation. Epicatechin Gallate (ECG) proved to be an effective antioxidant by reducing genotoxic damage. The results imply a strong genotoxic effect of TP in vitro on human lymphocytes and also a relevant antigenotoxic role of ECG in ameliorating steroid induced genotoxicity.