A new class of III–V based diluted magnetic semiconductors, specifically In1−xMnxAs (x≲0.2) and InAs/InMnAs multilayer structures, has been prepared by molecular beam epitaxy. The x‐ray diffraction measurements reveal that the incorporation of Mn can be predominantly either homogeneous (200 °C) or inhomogeneous (300 °C), depending on the growth temperature. Semiconducting properties of the films have been examined by optical absorption and Hall effect measurements, and it has been found the films of homogeneous alloy are n‐type and have a band gap which decreases with increasing Mn composition. Magnetization measurements indicate that the homogeneous alloy exhibits paramagnetic behavior, whereas ferromagnetic behavior dominates for the inhomogeneous case. The growth of GaMnAs has also been examined.