a b s t r a c t In the present work, room temperature (300 K) liquefied petroleum gas (LPG) sensor based on n-CdS/p-polyaniline thin film heterojunction has been fabricated using simple inexpensive electrodeposition technique. The CdS and polyaniline films were characterized for their structural and surface morpho-logical properties and LPG sensing performance of n-CdS/p-polyaniline heterojunction was studied. The X-ray diffraction (XRD) study revealed polycrystalline cubic phase for CdS films whereas the polyani-line films exhibited amorphous structure. Morphological analysis using field-emission scanning electron microscopy (FESEM) of the junction cross-section revealed the formation of a diffusion-free interface. The room temperature gas response towards N 2 , CO 2 and LPG was investigated and found to exhibit high response towards LPG as compared to N 2 and CO 2 . The maximum gas response of 80% was achieved with 95% stability for n-CdS/p-polyaniline heterojunction upon exposure of 1040 ppm LPG at room temperature.