We report the first measurement of minimum noise figure in lattice matched 0.15 mum x 64 mum AlGaAsSb/ In0.8Ga0.2As/AlGaAsSb metamorphic HEMTs (MHEMTs). A minimum noise figure of 0.82 dB is obtained at 15 GHz for applied gate and drain bias of -0.2 and 0.5 V, respectively increasing to 1.4 dB at 26 GHz. The devices show an unusual increase in minimum noise figure for frequencies below 10 GHz which may be attributed to an increase in the gate parasitic capacitance. (C) 2004 Elsevier Ltd. All rights reserved.