The drift velocity–electric field relationship for the ternary alloy InAs1−xPxhas been studied by the Monte Carlo methd. Random potential alloy scattering has been included in the calculations, along with polar optical scattering, intervalley scattering, acoustic scattering, piezoelectric scattering, and ionized impurity scattering. The low‐field electron mobility has also been calculated throughout the compositional range for the alloy.