OBJECTIVES: To assess the estimated prevalence of fibromyalgia syndrome (FM) among the adult population in United-Kingdom in the general population, using the London Fibromyalgia Epidemiology Study – Screening Questionnaire (LFESSQ) and American College of Rheumatology (ACR) classification criteria. METHODS: The LFES-SQ was administered to a representative community sample of 1500 subjects aged over 15 years, selected by the quota method. A positive screen was defined as: (1) meeting the 4-pain criteria alone (LFESSQ-4), or meeting both the 4-pain and 2-fatigue criteria (LFESSQ-6). The positive predictive value of LFESSQ-4 and LFESSQ-6, was estimated in different European countries, this questionnaire was submitted to a sample of rheumatology outpatients (n = 1.125), who were then examined by a trained rheumatologist to confirm or exclude the diagnosis of FM according to the 1990 American College of Rheumatology criteria. The prevalence of FM in the English general population was estimated by applying the predictive positive value to eligible community subjects (i.e., positive screens) in UK. RESULTS: The community sample is constituted of 765 females and 735 men. 7.8% screened positive for LFESSQ-4 (9.3% in females and 6.3% in males respectively). A total of 4.3% screened positive for LFESSQ-6 (5.5% in females and 3.0% in males respectively). Based on positive screens for LFESSQ 4 items (pain only), the prevalence of FM would be estimated at 2.8% (95% CI: [1.9-3.6] ; 3.3% in females and 2.2% in males respectively). The corresponding figure was 1.8 % (95% CI: [1.1-2.5] ; 2.3% in females and 1.3 % in males respectively) if positive screens for LFESSQ-6 (pain and fatigue) were considered. CONCLUSIONS:Our study confirms the results of publications in Canada, US or Spain, with slightly differences probably due to the different methodologies and populations used. A point prevalence of  1.8 % would translate in approximately 880 thousands of patients with FM in UK.