InSb enhancement‐mode, metal‐insulator‐semiconductor, field‐effect transistors with 1 &mgr;m gate lengths have been fabricated. When operated at room temperature with less than 0.5 V applied between the source and drain, the transistors have a static dynamic range in excess of 20 dB, a cut‐off frequency (fT) of 14 GHz and a transconductance, at 1 GHz, of 230 mS mm−1. Analysis of the parasitic capacitances indicates an intrinsicfTof about 90 GHz. The static electron mobility in the channel is 2×104cm2 V−1 s−1, so a carrier velocity of about 3.7×107cm s−1should be attained. This leads to a predicted frequency response of 84 GHz, in reasonable agreement with the intrinsic microwave data.