Introduction: The American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), often used in research in Brazil, although translated and adapted to the Portuguese language, had not had its validity and reliability tested yet. Objective: To assess the validity, reliability, and internal consistency of the ASES-PT for shoulder dysfunction. Materials and methods: Fifty individuals (26 women; mean age, 39 ± 13 years) participated in the validity assessment, and 38 (19 women; mean age, 37 ± 13 years old) in the reliability assessment, all having shoulder dysfunction. The participants completed the 36-Item Short-Form Health Survey (SF-36), the Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH), and the ASES-PT on two occasions with an interval of seven days. The convergent validity was assessed by use of the Spearman's rank correlation coeffi cient (ρ), and the analysis of the intrarater reliability used the intraclass correlation coeffi cient (ICC). The internal consistency was assessed by using Cronbach's alpha. Results: The ASES-PT scores correlated with the DASH scores (ρ = −0.69, P = 0.000) and with the "physical functioning" (ρ = 0.50, P = 0.000), "role limitation due to physical health" (ρ = 0.43, P = 0.002) and "bodily pain" domains (ρ = 0.60, P = 0.000) of the SF-36. The intrarater reliability of the ASES-PT proved to be adequate (ICC = 0.75, P = 0.000). The internal consistency (0.794) was satisfactory. Conclusion: The validity and reliability study of the ASES-PT supports its use for assessing shoulder dysfunction.