Objectives Validation of the Expanded Prostate Cancer Index Composite (EPIC) questionnaire translated to Portuguese. This is an evaluation tool of the effects of treatment on quality of life of patients with prostate cancer. Materials and Methods In order to translate and validate, several recommended methodological techniques in the literature were included: initial translation, synthesis of translation, board committee review and back translation. Sample included 40 patients with localized prostate cancer submitted to surgical retropubic radical prostatectomy from 2008 to 2010. Results The internal consistency analysis of the scales of the questionnaire resulted in alpha Cronbach coefficients “very good” (> 0.9) and “good” (> 0.8) to 8 of 14 domains. The higher coefficients (0.94) were assigned to sexual score, subscales incontinence and sexual function. Post-operatory follow-up ranged from 3 to 35 months, median 18.7 months. Conclusions The Brazilian version of EPIC is reliable and valid, and is a useful tool to evaluate the impact of retropubic radical prostatectomy on quality of life of Brazilian patients with localized prostate cancer, in national and internationals studies.