Spinel Ni-Co ferrite nanoparticles were prepared by simple combustion method and investigated through XRD, SEM, TEM and SAED analyses. Powder XRD and SAED data indicated the presence of nanocrystalline cubic spinel with single phase. The lattice parameters of the samples gradually increased with increasing Ni concentration and follow Vegard’s law. The crystallite size (D) and X-ray density of Ni-Co ferrite samples decreased with increasing Ni concentration. The spherical shape morphology of spinel Ni-Co ferrite particles and grain size (22.42, 21.32 and 20.62 nm for x = 0.0, 0.3 and 0. 5, respectively) was established by TEM. VSM analysis showed the typical magnetic properties of Ni-Co ferrite. The shape of the magnetic hysteresis (M-H) loops revealed the dependence of superparamagnetic behavior at room temperature (RT).