Complex formation processes between the SGH³GQH⁶GVH⁹G decapeptide fragment of alloferons 1 and 2 and copper(II) ions have been studied by potentiometric, UV-vis, circular dichroism (CD) and electron paramagnetic resonance (EPR) methods. This peptide contains two histidines (H⁶ and H⁹) and an N-terminal “albumin-like” Xaa-Yaa-His sequence. It was found that the decapeptide is able to bind 3 equiv of metal ions. The SGH³ sequence is the primary metal binding site and at pH 4 irrespective of the metal-to-ligand molar ratio (1 : 1, 2 : 1, 3 : 1) the CuL species with 4 N {NH₂, 2N⁻, N_Im} binding mode is formed. For the 2 : 1 metal-to-ligand molar ratio the Cu₂H₋₂L, Cu₂H₋₄L and Cu₂H₋₅L complexes, while for the 3 : 1 the Cu₃H₋₂L, Cu₃H₋₆L and Cu₂H₋₇L species dominate in solution. For the metal-to-ligand 2 : 1 and 3 : 1 molar ratios the Cu₃H₋₂L complex at 4–7 pH range is formed where the {NH₂, 2N⁻, N_Im}{N_Im}{N_Im} coordination mode of the decapeptide to copper(II) ions is suggested.