OBJECTIVES: To estimate the prevalence of possible fibromyalgia syndrome (FMS) among non-institutionalised French adults. METHODS: The LFES-SQ (London Fibromyalgia Epidemiology Study – Screening Questionnaire) were administered to 1018 individuals (>15 y.o.) representative of the French population (IPSOS using quota method). The LFES-SQ questionnaire allows to screen patients who might have FMS or a possible FMS; subjects are screened positive if they answered yes to all the questions. RESULTS: From positive subjects to have the accurate number of possible FMS patients (+) the following multiplication factors need to be used: multiplication factors of possible FM patients V number of (+)=Estimated Total FM cases in London/Number of Patients (+) in the London survey (i.e. 0.568 for the total population; 0.628 for women and 0.356 for men). On our 1018 subjects (529 women, 489 men), 133 were screened positive (80 women, 53 men). Therefore, using the multiplication factors we obtained 75.54 estimated FM cases (50.24 women, 18.87 men) i.e. an estimated prevalence of possible FM in France of 7.42%, 9.5% of women and 3.86% of men. CONCLUSIONS: Those data are higher than the ones obtained in the White study nor in the published prevalence of FMS in the literature, but they assess an estimated prevalence of possible FMS (without validating the diagnosis with a rheumatologist). Next step will be to calculate European multiplication factors and to generalise this survey in Europe.