Objective: Adherence to clinical guidelines for mental disorders among clinicians in industrialized countries is low. Research on guideline adherence among clinicians in lower- and middle-income countries is scarce. The purpose of this study was to evaluate the implementation of clinical guidelines for first-episode schizophrenia in the pilot phase of the Explicit Guarantees in Health (GES) program in Chile. Methods: Data were collected from 12 catchment areas in Chile, representing 58% of the public health system. Records for 20 patients from each site who were referred to the GES program with a tentative diagnosis of first-episode schizophrenia were reviewed. Adherence to first- and second-line antipsychotic treatments, use of diagnostic measures, and psychosocial interventions recommended in the guidelines were evaluated. Results: In the final sample of 110 patients, adherence to medication guidelines was good - 86% received the recommended first-line antipsychotic. Psychoeducation