Micrometer-scale piezoelectric PZT sensors for gravimetric applications were developed. The PZT thin films were fabricated with sol-gel PZT and were of 400 × 400 um2 working area. Optical microscopy, scanning electron microscopy, leakage current density analysis, and C-V characterization were employed to evaluate the structure as well as successfulness of the microfabrication process. A resonance measurement circuit, which transformed the resonance frequency signal to a DC level, was built to characterize the gravimetric ability of the PZT sensors. Change of mass on the PZT sensor can be detected by observing the DC shift at the output of the detection circuit.