The objective of this study was to evaluate interobserver reliability and the concurrent criterion validity of the adapted version of the International Skin Tear Advisory Panel (ISTAP) Skin Tear Classification System to Brazilian Portuguese. For the evaluation of interobserver reliability using the photograph database, 36 nurses classified 30 skin tears (STs) into three groups, according to its definitions (adapted version). For the evaluation through clinical application, 23 nurses classified 12 STs present in 8 thoracic and cardiovascular postoperative patients at a tertiary hospital in Sao Paulo, Brazil. For the data collection of patients, an enterostomal therapist nurse classified the ST found by simultaneously using the adapted ISTAP version and the Skin Tear Audit Research (STAR) Classification System to test the concurrent criterion validity. The average of 17.83 correct answers (SD = 5.03) resulted from 1080 photograph observations, with Fleiss κ = 0.279 (reasonable concordance level). The interobserver reliability in the clinical application resulted in a global correct answer percentage of 76.7% in 85 observations. The concurrent criterion validity was attested by the total correlation (r = 1) between ISTAP and STAR. The ISTAP classification for ST is a reliable instrument and also valid in Brazil, making it another option to be used in clinical practice.