Abstract Interaction of Cu complex (Salen= N, N´-ethylene bis (salicylideneimine)) with Bovine Serum Albumin (BSA) was studied by absorption spectroscopy, competitive binding study and thermal denaturation study. The protein binding affinity of Cu complex was found to be (3.0×104M−1). The binding plot obtained from the absorption titration data gives a binding constant of 3.5 (± 0.1)×104 M-1. It was found that the charge transfer band of the metal complex was perturbed in the presence of BSA. The thermodynamic parameters (ΔHº > 0 and ΔSº> 0) showed that the hydrophobic interaction leads to the increasing entropy brought about by interaction with the complex. The negative ΔGº values for interaction of BSA with the Cu complex indicate the spontaneity of the complexation. The thermodynamic parameters such as ∆G˚b, ∆H˚b, ∆S˚b were calculated by analyzing the UV/Vis data with a simple binding model. These thermodynamic parameters indicated that hydrophobic force play a major role in the binding.