A study was carried comparing the resazurina and MTT methods as indicators of indirect measure of cellular survival applied to valuated cytotoxic activity in order to assess the suitability of each of the two detection systems. The comparison was made through the valuation of cytotoxicity on three cell lines derived from human tumors: HEp-2, HT-29 and HeLa, evaluating three synthetic compounds during a treatment period of 48 hours using as a reference activity Doxorubicin HCl. The results obtained by the two methods showed a similar performance under the conditions tested in cell lines