The paper demonstrates the development of Dodecyl benzene sulphonic acid (DBSA) doped polyaniline (PANI) nanoparticles based ammonia gas sensor. DBSA doped PANI nanoparticles have been synthesized by chemical oxidative polymerization of aniline monomer in the presence of DBSA. The UV - Visible spectroscopy and X-ray diffraction measurements are used to confirm the formation of PANI and its doping by DBSA, whereas SEM images are used to see the formation of nanoparticles of PANI. The chloroform dispersion of synthesized PANI-DBSA was spin coated over prefabricated interdigitated Pt patterned glass substrate to realize porous gas sensing active layer. The sensor displays good response at 100 ppm ammonia concentration and can repeatedly detect ammonia with relative response of 5.5. Besides, this sensor development, an analysis of sensor performance against temperature variations is done to check thermal stability of the sensor. Effect of thin film thickness variations on relative response of the sensor is also analyzed. The experiments have been carried out at different concentrations which show that when concentration increases relative response and recovery time increase and response time decreases. © 2018 IEEE.