An investigation of the parameters as aniline: MnO2 and temperature on synthesis of polyaniline/MnO2 composites was performed. The composites were chemically prepared in H2SO4 media using different aniline: MnO2 ratios at 0 degrees C. After the ratio optimization, the syntheses were performed at 20 degrees C. The polyaniline/MnO2 composites were characterized by scanning electron microscopy (SEM), ultraviolet-visible, near infrared and infrared spectroscopic techniques. Composites obtained with a uniform, homogeneous and thicker coating of polyaniline films under oxide was considered as the best condition for synthesis.