In this paper, two models for estimating monthly average daily global radiation on a horizontal surface have been applied to four different locations. The first one is an empirical model, originally formulated by Barbaro et al. (Solar Energy 20 (1978) 431). Some modifications have been suggested. The second one is a regression equation of the Angstrom type. The agreement between the measured and the computed values is remarkable, and the models are both recommended for use in Algeria and in any location with similar climatic parameters. (C) 2001 Elsevier Science Ltd. All rights reserved.