The Patient-Reported Outcomes Measurement Information System (PROMIS) provides accurate and efficient measurement of patient-reported outcomes. Developed in English using qualitative methods, PROMIS seeks to measure symptoms, such as pain and fatigue, and aspects of health-related quality of life across a wide variety of chronic diseases and conditions. OBJECTIVE: In order to enable participation of the rapidly growing Spanish-speaking population of the USA it was necessary to translate PROMIS banks from English into Spanish using methods that would ensure linguistic equivalence and cultural appropriateness. METHODS: Five hundred and twenty-two items were translated into Spanish using the FACIT Multilingual Translation Methodology which consists of the following twelve steps: (1) translatability review of existing English items, (2) creation of item definitions, (3) two simultaneous forward translations,(4) reconciliation of forward translations, (5) back translation of reconciliation, (6) expert review of back translation and previous steps, (7) preliminary finalization for pilot-testing, (8) harmonization, (9) quality assurance, (10) formatting, (11) cognitive testing with native speakers of Spanish and (12) analysis and finalization of translations based on qualitative data collected during pilot-testing. Recognizing the need to address diversity within the Spanish-speaking population of the USA, linguists from various Spanish-speaking regions across the globe were recruited to achieve a universal Spanish translation. RESULTS: Some of the linguistic challenges encountered during the translation process as well as the language solutions for resolving difficulties associated with the cultural and linguistic heterogeneity of the Spanish-speaking population residing in the USA will be highlighted in this presentation. CONCLUSIONS: Future research includes further validation of the Spanish translations using psychometric testing of the equivalence of banks in English and Spanish, including assessment of differential item functioning across different cultural groups. The translation of additional items into Spanish and into other languages is also explored in this presentation.