SUMMARY Introduction The evaluation of patients with hyperhidrosis (HH) can be accomplished, among other ways, through questionnaires and scales. The Hyperhidrosis Disease Severity Scale (HDSS) has been used as a simple and quick tool to perform this evaluation. Although HDSS has been well established in several languages, it has not been translated into Portuguese, restricting its specific use for Brazilian patients. The aim of this study was to translate HDSS into Portuguese and validate it in a sample of Brazilian subjects. Method 290 Brazilian patients (69% women, with a mean age of 28.7±9.6 years and BMI 22.4±3.9 kg/m2) diagnosed with HH were evaluated using HDSS, Quality of Life Questionnaire (QLQ) and Sweating Evolution Questionnaire (SEQ) before and after a five-week oxybutynin treatment. Regarding validation, an association between HDSS results and two other questionnaires was performed. To analyze HDSS sensitivity, evaluation of effects pre- and post-treatment with oxybutynin was conducted. Furthermore, HDSS reproducibility was analyzed in a subsample in which the scale was applied again after 7 days of the first follow-up appointment. Results There was statistical correlation between HDSS and QLQ and between HDSS and SEQ before treatment and after 5 weeks. Additionally, HDSS was reproducible and sensitive to clinical changes after the treatment period. Conclusion The Portuguese version of HDSS has been validated and shown to be reproducible in a Brazilian sample. Therefore it can be used as a tool to improve medical assistance in patients with HH.