The non-local effect (NLE) beyond the local-spin-density approximation (LSDA) for vacancy formation energies in Al, Cu, and Ni is examined using the generalized-gradient approximation of Perdew and Wang. The calculations are based on the full-potential Korringa-Kohn-Rostoker Green's-function method. The NLE reduces the vacancy formation energies obtained by the LSDA and leads to nice agreement with the experimental values. The lattice parameter dependence for vacancy formation energies is discussed. (C) 1998 Elsevier Science B.V. All rights reserved.