Аннотация:Bis-(3,5-di-tert-butyl-4-hydroxyphenyl)dimethyltin(Me-3) and (3,5–di–tert–butyl–4–hydroxyphenylthiolate) triphenyl tin (Me-5) were used as chemotherapeutic agents. Groups of animals were formed as follows: I (experimental) - Me-3 at a dose of 75mg / kg; II (experimental) - Me-5 at a dose of 50 mg / kg; III (control group) - without pharmacological substances. The compounds were injected intraperitoneally daily for 5 days. All animals were euthanized since 21 days after the tumor cells transplantation. The antitumor effect was estimated by the percentage of tumor growth inhibition by weight (%). After the intraperitoneal injection of Me-3 and Me-5 there was revealed an inhibition of growth by weight of Lewis epidermoid carcinoma’s primary node for all experimental groups, 23.7% and 28%respectively. Conclusions: The injection of organotin compounds with different ligand groups allows us to suggest a biocidal activity of the organotin component on the primary tumor node cells.