The new ligand 2-acetyl-2-thiazoline thiosemicarbazone (HATtsc) and the complexes [Co(ATtsc)(2)](2)[CoCl(4)]·2H(2)O (1), [Co(ATtsc)(2)]NO(3)·H(2)O (2), [Ni(HATtsc)(2)](NO(3))(2) (3), [ZnCl(2)(HATtsc)]·CH(3)CN (4), [{CdCl(HATtsc)}(2)(μ-Cl)(2)]·2H(2)O (5) and [{Cd(NO(3))(HATtsc)}(2)(μ-NO(3))(2)] (6) were isolated and characterized by a variety of physico-chemical techniques and X-ray diffraction. The structure of HATtsc in 1 and 2 presented a thiolate form while in 3-6 the thione form was present, as it was in free ligand. In addition, we studied the antibacterial activity of the ligand and complexes 2-6 against some representative bacteria. Cd(II) complexes were more active against Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Bacillus subtilis than organic ligand. Conversely, Cd(II) compounds seemed to interfere in the cell separation of B. subtilis.