Silicon (Si)–nanopolyaniline (PAni) conducting platform has been electrochemically developed for the sensitive sensing of ammonia. The nano PAni films are formed through the assembly of nano granules of the polymer. The average height of the film is in the range of 50nm. The electrical conductivity of the Si–PAni is influenced in the presence of ammonia. The response of this conductometric sensor is almost linear within 5–50ppm of ammonia. The response and the recovery times are observed to be 10 and 60s, respectively for 10ppm of ammonia. The response time of the sensor for other concentrations (viz. 20, 30, 40, 50 and 60ppm ammonia) is also in the range of 10±2s. However, the recovery of the sensor takes slightly longer time (70±3s) in case of higher concentrations (≥40ppm) of ammonia.