Co-Ni alloy thin films were electrodeposited from sulfate baths at various solution pH values (1.5-5.5) ±0.1. The deposition kinetics of the films was studied using linear sweep voltametry (LSV). XRD studies exhibited fcc and hcp phases for Co-Ni alloys deposited at low and high pH ranges, respectively. EDAX studies showed that the cobalt content increased and nickel content decreased with increase in solution pH. The surface morphology of Co-Ni films were analyzed by scanning electron microscopy. It is found that the Co-Ni alloys synthesized at low pH exhibited soft magnetic properties and the films deposited at higher values revealed hard magnetic properties and the results are discussed.