We report detection of micromolar levels of triglycerides using surface micromachined polysilicon cantilever beams. Enzymatic hydrolysis of triglycerides produces glycerol which alters the viscosity and density of the solution. This affects the dynamic properties of cantilever beams immersed in the solution. The change in the resonance frequency of the cantilever beams in the solution is measured using Doppler Vibrometry and the concentration of triglyceride is determined by comparing with a predetermined calibration plot. © 2007 IEEE.