The diamagnetic drift frequency impact on the ballooning stability of INTOR-like tokamaks that contain a Maxwellian energetic ion species is investigated. The energetic ion diamagnetic drift frequency contribution enhances the critical beta (βC) imposed by ballooning modes with toroidal mode numbers n ≥ 7 by a factor of 1.2 to 1.3 above the corresponding limits obtained when the plasma consists of only thermal species.