The energy matrices for combined crystal field-spin orbit perturbation of the d1 and d9 configurations in trigonal bipyramidal environment have been constructed. Basis functions are selected according to thŵ eakand strong-crystalline-field approximations, and the generalized D>(a, ß, y) rotation matrices for angularmomenta eigenfunctions (js/2,5/2; 4/2, 2) are constructed and used to determine their transformation properties. The crystal-field matrix elements are expressed in terms of the parameters Dq and Db. Secular determinants resulting from either approximation are equivalent and indicate perturbation of the d orbitals into five energy levels. Spacing between these energy levels depends on the relative magnitudes of crystallinefield parameters and spin-orbit coupling constants, so in their generalized forms, the energy matrices are applicable to any d1 or d9 configuration in trigonal bipyramidal environment.