PURPOSE: To adapt the Ostomy Skin Tool (discoloration, erosion, and tissue overgrowth) to the Brazilian culture and to analyze psychometric properties of the adapted version. DESIGN: Psychometric (methodologic) evaluation of the instrument. SUBJECTS AND SETTING: Three ostomy/enterostomal therapy nurses evaluated the extent and severity of peristomal skin conditions in a sample of 109 adults 18 years or older with peristomal skin complications. These participants were receiving care in an ambulatory care center in outpatient health services in Sao Paulo and Curitiba, Brazil. In addition, interobserver reliability was measured using a group of 129 nurse participants who attended the Brazilian Congress of Stomatherapy held from November 12 to 15, 2017, in Belo Horizonte, a city located in the state of Minas Gerais, Brazil. Nurse participants assessed the descriptions of peristomal skin complications of the Portuguese version, using the same photographs used in the original DET score, purposely placed out of original order. METHODS: The study was performed in 2 stages. The instrument was translated into Brazilian Portuguese by 2 bilingual translators, and back-translated into English. The back-translated version was sent to one of the developers of the instrument for additional evaluation. During stage 2, content validity was evaluated by 7 nurses with expertise in ostomy and peristomal skin care. Convergent validity was evaluated by correlating the severity of peristomal skin complications to pain intensity. Discriminant validity was evaluated based on type and time of ostomy creation, presence of retraction, and preoperative stoma site marking. Finally, interrater reliability was evaluated using standardized photograph evaluation reproduced in the same sequence as the original English language version of the instrument, along with paired scores from assessment of adults living with an ostomy generated by an investigator and nurse data collectors. RESULTS: The Content Validity Index for the Ostomy Skin Tool was 0.83. Levels of mild agreements were obtained for the nurses' observations in the evaluation of peristomal skin complications using standardized photographs (κ= 0.314). In contrast, moderate to almost perfect agreements were obtained when scores were compared in the clinical setting (κ= 0.48-0.93, according to the domains). Positive correlations between the instrument and pain intensity (r = 0.44; P = .001) indicate convergent validity of the adapted version of the Ostomy Skin Tool. In contrast, analysis of discriminant validity was mixed and definitive conclusions about this form of construct validity cannot be made based on this study. CONCLUSION: This study supports convergent validity and interrater reliability of the adapted version of the Ostomy Skin Tool.