New complexes of 2-amino-5-chloro-benzophenone-4-(R)- thiosernicarbazones [where R= H (HL1), C6H5- (HL2)] with Pd(II), Cd(II) and Hg(II) chloride salts were synthesized. The stable diamagnetic complexes with 1:1 molar ratio were characterized by analytical data, molar conductivity and magnetic measurements, IR and H-1-NMR spectra. It was determined that the compounds, HL1 and HL2 exhibit bi- or tridentate ligand behaviour depending on the metal ion and the substituent on N-4 atom of the thiosemicarbazone. Cytotoxicity and proliferation experiments using K 562 chronic myeloid leukemia cell line and ECV 304 human umbilical vein endothelial cell line (HUVECs) imply that the Pd(II) and Hg(II) complexes with L-1 have allowable anti-leukemic effects. For K 562, the LD50 doses of [Pd(L-1)Cl]center dot C2H5OH and [Hg(L-1)Cl]center dot H2O were determined as 3.0 and 2.4 microgram/ml, respectively.