CMOS-MEMS resonators have found a broad usage in mass sensing applications especially in biomedical field. This paper reports theoretical calculations and Finite Element Method (FEM) simulation for a proposed microresonator for detection of acetone in exhaled breath as biomarker for diabetes. The resonator is 760 μm long and 340 μm wide with 1.461ng effective mass, 21.331 kHz natural resonance frequency, and 8.867 mHz/pg mass sensitivity. Deposition of 4 μm sensitive layer gives 781 μHz/ppm gas concentration sensitivity with minimum concentration detection of 1.28 ppm. The operating voltage of this resonator is below 50 V and the static sensing capacitance is 90.84 fF. Due to the reasonable mass sensitivity of the resonator, it could be used for mass sensing applications. © 2014 IEEE.