Introduction: Osteogenesis Imperfecta (OI), also popularly known as “Glass Bone Disease”, is a rare hereditary pathological condition that involves clinical and genetic modifications. Its main characteristic is bone fragility, which occurs due to the alteration in the function and structure of type I collagen, which significantly increases the chance of a fracture occurring. The perception of Quality of Life (QL) is an extremely important construct to assess, especially in patients with a pathology with such restrictive characteristics as OI. Objective: The main objective of this study was to perform the cross-cultural adaptation and validation of the OIQoL (Osteogenesis Imperfecta
Quality of Life) questionnaire for the Brazilian Portuguese language. Methodology: Thirty-five individuals of both sexes between 6 and 18 years old with OI participated in this study, with a mean age of 12.60 (SD=3.15). The cross-cultural adaptation followed the following steps: initial translation of the scale into Brazilian Portuguese; synthesis of translations; back translation; expert committee; and testing the pre-final version. The intraclass correlation coefficient (ICC) was used for statistical analysis of reliability (test-retest), Cronbach’s alpha for internal consistency, Spearman’s correlation for construct validity and exploratory factor analysis (EFA) for structural validity. Results: EFA identified one construct evaluated in each subscale of the OIQoL-Br: Being safe and careful; Fatigue; Reduced function; Pain; Fear; and Life Skills. Only item 23 had an inadequate factor load (<0.2) and the Fatigue subscale had low internal consistency (<0.7). All subscales had substantial reliability. And about the construct validity, most of the previously established hypotheses were confirmed. Conclusion: Our results showed that only the Fatigue subscale had low internal consistency and item 23 had a low factor loading value in the factor analysis performed, recommending its removal from the Fear subscale. But, in general, the OIQoL-Br is a valid and reliable instrument for evaluating aspects that involve the quality of life of patients between 6 and 18 years of age with Osteogenesis Imperfecta.