To investigate prevalence estimates of restless legs syndrome (RLS) in relation to insomnia complaints and daytime distress a questionnaire was sent to a randomly selected sample of 1962 inhabitants of Uppsala, Sweden. The questionnaire included questions about sleep and daytime distress and the standardized four-question set for epidemiological settings recommended by the International RLS Study Group. A positive diagnosis of RLS was established in 18.8% of all responders. When the optional question about frequency was applied 5.8% reported frequent symptoms. Insomnia symptoms and daytime distress were significantly associated with the frequency of RLS symptoms.