OBJECTIVES: Cognitive debriefing interviews are a key component of the translation and linguistic validation of PROs and a necessity when a PRO is to be used as a primary or secondary endpoint for an FDA label claim. The 2005 ISPOR principles of good practice report describes the objectives of debriefing, but little discussion has been undertaken into the methods for performing debriefing interviews as part of the translation and linguistic validation process. This abstract presents a pilot test of methodologies across countries. METHODS: A literature review was conducted on cognitive debriefing methodology, and different approaches were pilot tested in 10 countries. Three methodologies were selected for pilot testing: 1) Retrospective probing 2) Retrospective think aloud 3) Concurrent think aloud. RESULTS:  The literature review highlighted the methodologies and pros and cons of different approaches to cognitive debriefing, but no research was identified that addressed the issues of particular relevance in the translation and linguistic validation process. All three processes listed above proved suitable for a methodology for linguistic validation.  The Think Aloud technique provided a true sense of the respondent’s understanding of the translation but its suitability was particularly subject to cultural and individual differences.  Questionnaires of a personal nature (e.g. those pertaining to sex or bowel disorders) benefited from Retrospective Probing, since the patients could respond hypothetically.  The Retrospective Think Aloud technique elicited more information from some respondents, since it allowed them to discuss their personal experience.  Where the respondent had difficulty in understanding what was required of them, modifying the interview style proved beneficial. CONCLUSIONS: A combination of Retrospective Probing and Retrospective Think Aloud proved to be the optimum methodology across countries, but this was dependent on the culture, patient, and the nature of the PRO being translated.