Twenty one novel mixed ligand di-n-butyltin(IV) complexes [(n)Bu2SnAL] (A = substituted 4-acyl-5-pyrazolone, and L = fluorinated benzoic acid) were prepared by condensation of di-n-butyltin(IV) oxide with HL and HA in 1:1:1 molar ratio in refluxing methanol. All of the complexes were characterized by elemental analyses, IR, NMR ((1)H, (13)C, (119)Sn) and in four cases by X-ray diffraction. Cytotoxicity of the compounds was studied against two human cancer cell lines (KB and Hela) by means of the MTT assay compared to cisplatin, featuring IC?? values in the low micromolar range. Hela cancer cell apoptosis-induced by 2 was examined by flow cytometry analysis, and preliminary results showed that 2 at concentrations of more than 1.0 μM can induce apoptosis.