In the molecular beam epitaxial (MBE) growth of InxGa1−xAs, quite uniform and lattice‐matched In0.53Ga0.47As epilayers have been obtained over large‐size InP wafers. Composition variation of the epitaxial layer over an entire 2‐in. φ wafer is less than ±0.7%; that is, the difference of lattice mismatch between the center and the edge of the wafer is less than 1×10−3. Around the center, composition variation is less than ±0.25% over lateral dimension of 2.5 cm. In this 2‐in. φ epitaxial wafer, the relation between electron mobility and lattice mismatch is also studied.