In this letter we report the molecular beam epitaxial growth and characterization of InAs/GaSb superlattices grown on semi-insulating GaAs substrates for long wavelength infrared detectors. Photoconductive detectors fabricated from the superlattices showed photoresponse up to 12 &mgr;m and peak responsivity of 5.5 V/W with Johnson noise limited detectivity of1.33×109 cm Hz1/2/Wat 10.3 &mgr;m at 78 K. ©1997 American Institute of Physics.