Abstract. Short-wavelength (1 to 2.5 µm) and medium-wavelength (1 to 4.0 µm and 1 to 4.8 µm) 64 x 64 hybrid focal plane arrays (FPAs) have been developed. The short-wavelength (SWIR) arrays were developed for use in a prototype Airborne Imaging Spectrometer system. The medium-wavelength (MWIR) arrays are suitable for tactical missile seekers and strategic surveillance systems. The detector material is HgCdTe LPE grown on a sapphire substrate. The unit cell size is 52 µm x 52 µm, and the detectors are ion-implanted planar structures. The multiplexer is a surface- or buried-channel, four-phase charge-coupled device. The unit cell has a direct-injection FET and a storage capacitor. The current-voltage characteristics of the 64 x 64 detector arrays were measured at near-zero background using Si fan-out chips. For the detector arrays with a 2.5 µm cutoff, the mean RoA for 29 random elements was 2.7 x 106 cm2 at T = 150 K. The mean RoA was 3 x 104 cm2 at 120 K for detector arrays with a 4.6 µm cutoff. Both results were adequate for specific system applications. The arrays were also characterized at different temperatures, and the results are presented herein. The 64 x 64 SWIR and MWIR detector arrays were mated to a multiplexer, and the resulting FPAs were characterized under different operating conditions. Detailed characterization results are presented.