The aim of this research was to carry out the empirical validation of the clinical formulation model founded on basic processes and proposed by Castro and Angel (1998). A quasi-experimental trans-sectional descriptive and comparative design with three groups was used. Participants were thirty psychologists assigned to the three groups according to their academic background and clinical experience (novice, intermediate an expert). They received written information about a clinical case in order to formulate it using Castro and Angel’s model. Validity indexes were obtained by calculating the percentage of agreements between the formulations of the three groups and a reference formulation; a special instrument was designed for this purpose. The statistical tests H of Kruskal-Wallis and W of Kendall were also used. Results showed that, in general, the model oriented the development of the formulations in the majority of aspects regardless the clinician’s level of experience. This points out the empirical validity of the model; nevertheless, the levels of agreement were not high and the differences lie in one of the model’s basic categories. This is the fi rst study aimed at validating Castro and Angel’s model; its results will allow the