A method is reported for the determination of the surface recombination velocity by scanning electron microscopy; this method is based on an established relationship between the effective diffusion length of the minority carriers, the penetration depth of the electron beam, and the surface recombination velocity. Values of surface recombination velocity, up to about 2.5×106cm/sec were determined inn‐type GaAs with a bulk minority‐carrier lifetime of the order of 10−8–10−10sec; in GaAs, with carrier concentrations exceeding 1018cm−3, recombination velocity of about 3×106cm/sec represents a saturation value.