Background: There is a growing scientific interest in the effects of hallucinogens in general and the religious use of psychoactive brew ayahuasca in Brazil in particular. However, there is not yet a standard instrument used in Brazil to evaluate the effects of hallucinogens. The Hallucinogen Rating Scale (HRS) is a questionnaire widely used in the U.S. and Europe to evaluate the effects of several psychoactive substances, including hallucinogens. Objective: To translate and adapt the HRS to Brazilian Portuguese. Method: We followed three steps: 1) the authors of the article translated the HRS into Portuguese, in order to establish an initial version; 2) two independent translators back-translated this version into English; 3) a revision committee produced a final version of the Brazilian Portuguese version. This final version was developed comparing the initial translations and back-translations, through a dialogic process with the author of the instrument. Results: A final Portuguese version of the HRS, following the guidelines for semantic and conceptual equivalence between English and Portuguese to describe hallucinogen-induced subjective states. Discussion: A Brazilian version of the HRS - an instrument widely used throughout the world to quantify effects of psychoactive drugs - provides a sensitive instrument for evaluation of the effects of hallucinogenic substances in Brazil.