Nickel ferrite (NiFe2O4) was prepared by co-precipitation technique and polyaniline-nickel ferrite (PANI- NiFe2O4) composites were prepared by in-situ chemical oxidative polymerization method with different weight percentages. Samples were characterized to understand their thermal properties such as TGA and DSC, electrical such as AC and DC conductivity and dielectric properties. The surface morphology and average grain size was investigated by scanning electron microscope analysis. Oxidizing agent played vital role to change conducting polyaniline to dielectric. This kind of behavior encouraged to study their dielectric properties. Results of dielectric studies showed that ferrites doped polyaniline may suitable for energy storage device and applications.