We have investigated chemical sensing properties of three polymeric films (organic and organometallic poly-ynes) by a surface acoustic wave (SAW) and surface transverse wave (STW) sensor, at room temperature. The sensor system, consisting of an acoustic two-port resonator operating at 433.92 and 380.8MHz, respectively, has been configured as a frequency oscillator, including an integrated electronic module. The polymeric membranes have been tested, at room temperature, toward gases (NO 2 , NO, NH 3 , CO, CH 4 , SO 2 , H 2 S in N 2 ), relative humidity (RH), and vapours (ethanol, acetone, ethyl-acetate) by showing high sensitivity and low selectivity. A comparison of sensing performance of our SAW RH sensors with a commercial hygrometer has been realised. Principal component analysis (PCA) has been applied as pattern recognition technique achieving good separation for the examined vapours, at tested low concentrations.