Acetone vapor sensing is important for environmental monitoring and non-invasive screening of diabetes mellitus (DM). Inhaling higher than 176 parts per million (ppm) acetone concentrations affects the respiratory system, while acetone in exhaled breath correlates with blood glucose and exhaling more than 1.8 ppm indicates the person is in danger of DM. DM is currently diagnosed invasively by measuring glucose level in blood, which is painful, and therefore inconvenient. This paper reports MEMS sensor device functionalized with blend of Chitosan/Polyethylene glycol polymers for acetone vapor sensing for possible non-invasive screening of diabetes. The sensor was experimentally tested using synthetic acetone vapor, and found to give linear response for 0.05-5 ppm acetone in air, with a sensitivity of 21 mV/ppm, good repeatability, response, and reversibility. Cross-sensitivity for 2-propanol and methanol was examined, where the responses of the sensor to 1 ppm concentration in air of these two analytes were found to be 24 and 33, respectively, less compared to its response to the same concentration of acetone. © 2001-2012 IEEE.