The design of an active three dimensional (3D) millimeter wave imaging system for personnel security screening using compressed sensing is presented in this work. The system is able to produce a high-resolution 3D reconstruction of the whole human body surface and reveal concealed objects under clothing. Innovative multistatic millimeter wave radar designs and algorithms, which have been previously validated, are combined to improve the reconstruction results over previous approaches. Compressed Sensing techniques are used to drastically reduce the number of sensors, thus simplifying the system design and fabrication. ææRepresentative simulation results showing good performance of the proposed system are provided and supported by several sample measurements.