We report on imaging at terahertz frequencies using a 3x5 Si MOSFET focal-plane array (FPA) processed by a 0.25-μm CMOS technology. Each pixel of the FPA consists of a 645-GHz patch antenna coupled to a FET detector and a 43-dB voltage amplifier with a 1.6-MHz bandwidth. We achieve a typical single-pixel responsivity of 80 kV/W and a noise-equivalent power (NEP) of 300 pW/√Hz at 30-kHz. The performance data of these all-CMOS devices pave the way for the realization of broad-band THz detectors and FPAs for video-rate active imaging on the basis of established low-cost and integration-friendly CMOS technology.© (2009) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.