The cytotoxic activities of diorganotin(IV) complexes of some xanthate derivatives; R2Sn(SSCOR'), where R = Me, Bu(n), Ph and R' = C6H11 - (CyX), CH3NHCHCH2 - (MAEX), (CH3)2NCH2CH2 - (DMAEX), (CH3)2NCH2CH(CH3) - (DMAIX) and (C2H5)2NCH2CH2 - (DEAEX), have been studied against Hep-2, Hela, RD, L20B and BGM cell lines using the MTT-colorimetric assay. The present results indicated that moderate activities were demonstrated by the xanthate complexes of Bu(n)2Sn(IV) against four cell lines, whereas no cytotoxic activities were exhibited by both Me2Sn(IV) and Ph2Sn(IV) complexes of the xanthates. These activities were compared with the cytotoxic activities of two reference standards; the cisplatin and paraplatin complexes. The significance of these results is discussed.