Résumé : Nine new substituted triphenyltin benzoates of the type Ar3SnOOCC6H2XYZ [X = Y = H, Z = 2‐OCH3 and 4‐F; X = H, Y = 3‐F, Z = 5‐F; X = H, Y = 2‐OH, Z = 5‐Cl, 5‐NH2, 5‐OCH3 and 5‐SO3H; X = 2‐OH, Y = 3‐CH(CH3)2 and Z = 5‐CH(CH3)2] were prepared and possess considerable in vitro antitumor activity against two human tumor cell lines (MCF‐7, a mammary tumor, and WiDr, a colon carcinoma) comparable with that of mitomycin C. Copyright © 1992 John Wiley & Sons Ltd.