The self-efficacy belief relates to pain perception and physical and psychiatric functionality. The goal of this study was to validate to the Portuguese language the Chronic Pain Self-efficacy Scale (CPSS). The subjects were 132 chronic pain patients with pain from several etiologies. The scale validity in the Portuguese language was confirmed by factor analyzis, which maintained the 3 factors and 22 items of the original scale; the accounted variance was 60,8%. The reliability, analyzed by Cronbach´s alpha coefficient, were 0,76 - 0,92 to the factors and 0,94 to the total scale. The convergent validity, verified by the comparison with the Portuguese version of the Chronic Pain Self-efficacy Scale and Beck Depression Inventory (IDB) showed significantly negative correlation. This study made available to the Portuguese language a valid and reliable instrument to assess self-efficacy in chronic pain patients.