[en] Co-Ni-P alloy thin films have been electrodeposited from sulfate baths at various solution pH and current density values. The effect of pH and current density on compositional, structural, morphological, and magnetic properties of these films was investigated by EDAX (energy dispersive analysis of X-ray spectroscopy), XRD (X-ray diffractometer system), AFM (atomic force microscope) and VSM (vibrating sample magnetometer). The reaction mechanism of individual deposition of Co, Ni and Co-Ni-P were investigated by cyclic voltammetry. The EDAX results revealed that cobalt and phosphorous content were high and nickel content was low at high solution pH and at low current density. X-ray diffraction studies exhibit that the intensity of hcp and Co-Ni-P amorphous phases increases and the intensity of fcc phase decreased when increasing the solution pH and decreasing the value of current density. The surface morphology of the films were observed by AFM. The deposited films exhibit hard magnetic properties at high pH value and soft magnetic properties at low pH value