The “Modulated Friction Inertial Drive (MFID) principle” is presented as a locomotion solution for mmsize micro robots dealing with both size constraints and limitations in terms of power consumption. Based on one of the configurations of this locomotion principle a locomotion module (10 × 10 mm2) with two degrees of freedom (X,ThetaZ) has been developed. It consists of two horizontally vibrating masses actuated by electrostatic comb drives and fabricated by DRIE on a SOI wafer. The design as well as calculated and measured actuator displacements and resonance frequencies are presented. First locomotion experiments have shown a linear velocity of 0.207 mm/s for a driving voltage of 30 Vp2p and a power consumption of only 16.6 μW.