The temperature and field dependence of the magnetization of the hexagonal intermetallic compounds, LuxTm2−xCo1 7 (x=0, 2/3, 4/3, 2) has been determined as a function of crystallographic direction. All specimens were single crystal spheres, and measurements were made in the temperature range 77.4K to 450K in applied fields up to 13 KOe. The anisotropy constants K1 and K1 were determined and the anisotropy behavior was found to obey the single ion model.