The aim of this study was to evaluate the reliability of four scales of pain intensity measurement in patients with musculoskeletal disorders and low educational level. Verbal rating scale, face scale, visual analogy scale, and numeric scale were used. Reliability was evaluated by the stability (test-retest) using Intraclass Correlation Coefficient, and the participant's perception on understanding and completing the scale forms. Numerical scale presented the highest reliability value (r = 0.99), and verbal rating scale, had the lowest reliability value (r = 0.88). The numerical scale was considered the easiest to understand and to complete, while the most difficult was the visual analogy scale.