Future applications of ion implantation require a knowledge of how the retention of implanted ions varies with angle of ion incidence. In this work the retention of 150-keV Ar,Ti,Cr,and Ta ions in AISI-M50 and 52100 bearing steels was measured for incidence angles up to 60° off normal. Fluences between 3×1015 and 3×1017/cm2 were used, typically on 3/8” diameter cylindrical samples. Retention was measured for Ar, Ti, and Cr by ion induced x-ray emission and for Ta by backscattering of He ions. Range and sputtering parameters needed for model calculations were experimentally determined from Ta-implanted thin Fe film samples. Generally, at the low-fluence limit a near-cos θ dependence obtained while at the high-fluence limit a (cos θ)8/3 dependence applied where θ is the angle between the sample normal and the beam direction.