Present work deals with the development of capacitive porous alumina based trace moisture sensor in the range of 50 to 500 ppm(V) fabricated by low cost sol-gel technique. For its commercial usefulness, the cross-sensitivities due to the presence of organic vapours like ethanol, methanol, acetone and benzene are studied. The effects of ambient temperature have also been studied. Experimental results show that moisture sensor is responsive to the polar organic vapours but has almost negligible response to the nonpolar molecules like benzene. However compared to the moisture sensitivity, the sensor response to the organic vapours is very small. copy; 2008 IEEE.