Thiosemicarbazide derivatives are widely used in medicine to treat various types of diseases [1]. They all possess a wide range of donor atoms and form with metal ions bio-active coordination compounds of various composition, structure and properties. In this connection, the synthesis and study of new biometal complexes with similar ligands is of both scientific and practical interest. The aim of the given work is to establish optimum conditions of synthesis, to determine the composition, structure, physicochemical and anticancer properties of 2-formylpyridine N-(2-methylphenyl)thiosemicarbazone (L1) and N-(3-methylphenyl)-thiosemicarbazone (L2) and copper(II) complexes with these ligands of general formula Cu(L1-2-H), where X- Сl-, Br-, NO3 - . N O H2N HN S NH R1 R2 + L1 : R1 = CH3 , R2 = H; N N NH L2 : R1 = H, R = CH3 . S NH R1 R2 L1-2 The anticancer effect of thiosemicarbazones L1 and L2, and of copper(II) complexes was studied “in vitro” on breast (MCF-7) and prostate (LNCaP) cancer cells [2, 3]. It has been established that at the concentration 10-5 mol/l both initial thiosemicarbazones (L1 and L2) inhibit at 100% the growth and reproduction of the above mentioned cancer cells. At the concentration 10-6 mol/l the thiosemicarbazone L1 inhibits 36,9 ± 3,8% of breast cancer cells (MCF-7) and 13,5 ± 5,2% of prostate cancer cells (LNCaP), but L2 - 48,3 ± 3,0 and 45,4% ± 1,9% of the respective cancer cells. At the concentration 10-7 mol/l the thiosemicarbazone L1 inhibits 25,1 ± 3,8 and L2 - 18,4 ± 7,7% of breast cancer cells (MCF-7), but do not display activity towards the prostate cancer cells. At the concentration 10-8 mol/l these substances do not display anticancer activity towards all types of cancer cells. It has been established that the anticancer activity of the studied substances is influenced by the position of the methyl group in the thiosemicarbazone phenyl fragment: the replacement of position 2 by 3 decreases the anticancer activity towards breast cancer cells (MCF-7) and increases the anticancer activity towards prostate cancer cells (LNCaP). The anticancer effect of copper(II) complexes does not exceed the ligands activity and varies in the above mentioned limits.