In this paper, the influence of calcination temperature on the degree of crystallinityand morphology of tetragonal copper ferrite nanoparticleswas investigated usingdifferent characterization techniques, i.e., X-ray diffraction (XRD), transmission electron microscopy (TEM)and field emission scanning electron microscope (FESEM).Copper ferrite nanoparticles were fabricated by a thermal-treatment method using a solution that contained poly vinyl alcohol (PVA). Heat treatment was conducted at temperatures between 673 and 823 K, and final products had different crystallite sizes ranging from11 to 42 nm. Magnetic studies were executed by VSM and ESR, which substantiated the ferromagnetic behavior and the unpaired electron spin, respectively. The results disclosed that the saturation magnetization (Ms) and the remanent magnetization (Mr) increased as the calcination temperature increased.