The theory of spin-restricted Brueckner orbitals for high-spin open-shell coupled-cluster wavefunctions is presented. The orbitals are based on single-excitation amplitudes constructed using the symmetric spin-orbital basis coupled-cluster method of Jayatilaka and Lee. It is shown how this approach may be easily implemented within existing open-shell coupled-cluster programs. The method's performance is compared to conventional spin-unrestricted Brueckner orbitals for (C) over tilde(2)A(2)NO(2) and (X) over tilde(2)A(2)'NO3, for which instabilities in the Hartree-Fock reference determinant cause serious difficulties for highly correlated wavefunctions. (C) 1997 American Institute of Physics. [S0021-9606(97)03747-1].