Altered sleep and wakefulness affect individuals' mood, memory, and psychomotor performance and thus directly impact their quality of life. Tools to analyze the quality of these factors should be available for clinical evaluation. This study aimed to translate into Brazilian Portuguese and culturally adapt the Patient-Reported Outcomes Measurement Information System (PROMIS), specifically the sleep and wake disturbances domains. The translation and cultural adaptation processes followed the guidelines proposed by the Functional Assessment of Chronic Illness Therapy (FACIT) organization. The methodology included translation, reconciliation, back-translation, review by PROMIS, review by independent reviewers, pretest, and incorporation of the results into the final version. The Portuguese version of the sleep and wake disturbances domains presents semantic, idiomatic, cultural, and conceptual equivalence with the items in the source language.