Intense room temperature emission at 3.7 mu m is reported from light-emitting diodes (LEDs) which contain ten InAsSb/InAs type II multi quantum wells grown by molecular beam epitaxy. Interpretation of the spectra revealed the existence of two confined heavy-hole states with emission peaks of 0.33 and 0.37 eV at 4 K. Analysis of the temperature dependence of the electroluminescence shows that emission occurred predominantly from the excited heavy-hole state at high temperatures. At room temperature, the devices produced a quasi-cw power of 12 mu W at 100 mA injection current corresponding to an internal quantum efficiency of 2.2%.