The problem of torsion of a prismatic body with multiply-connected, cross section is considered from the view-point of two basic variationa'l principles in the theory of elasticity, viz., the principle of minimum potential energy and the principle of complementary energy. According to the former, among all admissible states of strain, in the sense of being derived from sets of displacements chat satisify the specified displacement boundary conditions, the true state renders the potential energy of the system a minimum. In the latter, among all admissible states in the sense of satisfying the equilibrium conditions and the specified stress boundary conditions, the true state renders the complementary energy of the elastic body a minimum.