Background and purpose: Restless legs syndrome (RLS) is a sensorimotor disorder with a general-population prevalence of 5-10%. Although, data on the prevalence of clinically diagnosed RLS are limited, and there are none regarding incidence, a shortfall compared with general-population values is likely, as not all patients are driven to consult. There may also be poor awareness of the condition among primary care physicians (PCPs).Patients and methods: The General Practice Research Database was used to gather prevalence and incidence data from UK PCPs and to investigate PCP awareness over the period 1994-1998. A total of 1,561,692 persons were covered by the database on January 1, 1999.Results: A diagnosis of RLS was registered in 3877 patients, giving a prevalence of 0.25%. Incidence values were also low (41.0 per 100,000 person-years), increased with age and were higher in women than in men. Although, at least one RLS diagnosis was made in 94% of medium-to-large practices, sufferers were more likely than age/sex-matched controls to be diagnosed with conditions commonly confused with RLS in 2 years before receiving their RLS diagnosis. Furthermore, at the time of diagnosis, many sufferers were prescribed medications not effective in RLS (principally, oxerutins and quinine).Conclusion: These data are largely consistent with a lack of awareness of RLS among PCPs in the UK in the period studied. q