ABSTRACT. In 2005 a new phase for Primary Health Care (PHC) in Portugal began, leading to the voluntary and independent creation of Family Health Units. The impact of this reform is now being witnessed, which justifies the need to evaluate its results as far as best practices in PHC are concerned.This work uses a Value-Based Data Envelopment Analysis (DEA) method, which combines an additive DEA model with Multi-Criteria Decision Analysis (MCDA) concepts, to allow incorporating managerial preferences in the performance assessment of 12 health centres in a Portuguese region. Two models are presented for evaluating access to PHC, which resulted from discussions with a group of decision makers.This analysis helped the decision makers in the identification of best practices, sources of inefficiency and gaps relatively to the best practices, thus leading to shape opportunities for improvement.