The consequences of traumatic brain injury (TBI) for health-related quality of life (HRQoL) are poorly investigated, and a TBI-specific instrument has not previously been available. The cross-cultural development of a new measure to assess HRQoL after TBI is described here. An international TBI Task Force derived a conceptual model from previous work, constructed an initial item bank of 148 items, and then reduced the item set through two successive multicenter validation studies. The first study, with eight language versions of the QOLIBRI, recruited 1528 participants with TBI, and the second with six language versions, recruited 921 participants. The data from 795 participants from the second study who had complete Glasgow Coma Scale (GCS) and Glasgow Outcome Scale (GOS) data were used to finalize the instrument. The final version of the QOLIBRI consists of 37 items in six scales (see Appendix ). Satisfaction is assessed in the areas of "Cognition," "Self," "Daily Life and Autonomy," and "Social Relationships," and feeling bothered by "Emotions," and "Physical Problems." The QOLIBRI scales meet standard psychometric criteria (internal consistency, alpha = 0.75-0.89, test-retest reliability, r(tt) = 0.78-0.85). Test-retest reliability (r(tt) = 0.68-0.87) as well as internal consistency (alpha = 0.81-0.91) were also good in a subgroup of participants with lower cognitive performance. Although there is one strong HRQoL factor, a six-scale structure explaining additional variance was validated by exploratory and confirmatory factor analyses, and with Rasch modeling. The QOLIBRI is a new cross-culturally developed instrument for assessing HRQoL after TBI that fulfills standard psychometric criteria. It is potentially useful for clinicians and researchers conducting clinical trials, for assessing the impact of rehabilitation or other interventions, and for carrying out epidemiological surveys.