Cobalt zinc ferrite nanoparticles, Co_xZn_1-xFe₂O₄(x=0.3, 0.5 and 0.7), have been prepared by the co-precipitation method and annealed at different temperatures. The structural and magnetic properties of the samples were determined and characterized by X-ray analysis showed that the samples were cubic spinel. Enhancement of crystallinity and particle size was observed with the increase in annealing temperatures. The increase in cobalt concentration in zinc ferrite nanoparticles resulted in the decrease of lattice parameter, unit cell volume and increase X-ray density were observed. Thermo gravimetric and differential thermal analysis (TG/DTA) method was used to confirm the formation of cobalt zinc ferrite nanoparticles. FTIR spectra confirm that the presence of metal oxide stretching vibration is attributed to the formation of cobalt zinc ferrite nanoparticles. The cobalt zinc ferrite nanoparticles annealed at 600 °C were characterized by using FESEM with EDAX, FETEM with SAED pattern. The surface morphology of cobalt zinc ferrite nanoparticles studied through FESEM and FETEM indicate that the particles were in spherical shape. EDAX analysis revealed the presence of Co, Zn, Fe and O content in cobalt zinc ferrite nanoparticles, and it’s varied with the Co concentration. The M–H curve of cobalt zinc ferrite nanoparticles shows a ferromagnetic behavior at room temperature. The magnetic measurements showed that the saturation magnetization and coercivity increased with increasing the cobalt content in zinc ferrite nanoparticles, and it is suitable for magnetic devices. The electrochemical performance of the nickel zinc ferrite nanoparticles was investigated by CV analysis. The higher capacitance value 449 Fg^-1 was observed for the scanning rate 5mVs^-1for Ni_0.7Zn_0.3Fe₂O₄ reflecting the good quality of nickel zinc ferrite nanoparticles, and it was suitable for supercapacitor application.