The results of self-consistent hybrid simulations of an oblique collisionless, supercritical shock are presented in order to study the possibility that field-aligned ion beams (FABs) formed by direct reflection could contain alpha particles. Alpha particles are included in the simulations self-consistently, with care taken to ensure that sufficient simulation particles are present to give reasonable statistics. It is found that alpha particles can beackstream from a shock with &thgr;Bn=45¿, but less readily than protons. The deficit of alpha particles in the FABs, expressed as a relative density ratio to H+ (normalized to the solar wind He++ to H+ density ratio), varies between about 0.1 and <0.01, and depends strongly on the upstream H+ and He++ temperatures. ¿ American Geophysical Union 1989