We report the growth by low‐pressure metalorganic vapor phase epitaxy of lattice‐matched InGaAs on InP substrates using tertiarybutylarsine as the arsenic source. The grown layers are uniform in composition and are consistentlyntype with low background carrier concentrations (2–3×1015/cm3). Room‐temperature mobility as high as 11 200 cm2/V s with a corresponding 77 °K mobility of 57 000 cm2/V s are measured. Photoluminescence gave a strong narrow peak with a full width half maximum=3.1 meV, with no evidence of carbon incorporation.