Three new complexes, [Cu(phen)(L-argH+)Cl]Cl . 2.5H(2)O (1), [Cu(phen)(L-leu)(H2O)]Cl . 2.5H(2)O (2) and [Cu(phen)(L-met)(H2O)]Cl . 2H(2)O (3), where phen = 1,10-phenanthroline, L-arg = L-argininate, L-leu = L-leucinate, and L-met = L-methioninate, were synthesized and characterized by elemental analysis, molar conductivity, IR and UV-Vis spectroscopies. Complex 1 was structurally characterized by single-crystal X-ray diffraction. The superoxide dismutase (SOD)-like activities of the three complexes were determined by the improved NBT method. The results show that the complexes have high superoxide dismutase-like activities and may act as good mimics for superoxide dismutases.