We present results on the identification of native vacancies in GaAs by positron annihilation. It is shown that the correlation of positron lifetime and Doppler broadening coincidence spectroscopy with theoretical calculations allows the unambiguous defect identification of vacancies in both sublattices of GaAs. This is demonstrated for V-Ga-Te-As and V-As-Si-Ga, complexes. However, the identification of complexes is limited to the case of next nearest neighbor complexes. whereas in other cases only the sublattice can be determined.