OBJECTIVE: To assess the relationship of nocturia to somatic health, mental health and bodily pain. SUBJECTS AND METHODS: A randomly selected group of men and women aged 20-64 years, living in three small municipalities in northern Sweden, or in the city of Ostersund or in Stockholm, were sent a postal questionnaire containing questions on somatic and mental health, satisfaction with life, pain, nocturnal voiding, work and sick-listing from work. RESULTS: Reports (from 1948 respondents) on poor somatic and mental health and on pain all increased in parallel with increasing frequency of nocturnal voids. In a multiple logistic regression analysis with sex, age, somatic health, mental health and bodily pain as the independent variables, significant independent correlates (odds ratios, confidence intervals) of nocturnal micturition (two or more episodes vs none or one) were: age 45-59 vs 20-44 years, 1.9 (1.3-2.7), > or =60 vs 20-44 years, 3.8 (2.4-6.0); somatic health, poor vs good, 2.3 (1.4-3.7); mental health, poor vs good, 1.9 (1.2-3.0); pain, rather mild vs very mild or none, 1.5 (1.0-2.3); rather severe vs very mild or none, 1.9 (1.1-3.2); and very severe vs very mild or none, 6.0 (2.5-14.0). Gender was deleted by the logistic model. Sick-listing for > or = 60 days during the past year was reported by 4.9%, 10.6%, 5.6% and 38.9% of the men with none, one, two or > or = three nocturnal voids, respectively, and by 10%, 12.4%, 23% and 46.7% (both P < 0.001) of the corresponding women, respectively. Life satisfaction decreased in parallel with increased nocturia. CONCLUSION: The impairment of both somatic and mental health was associated with increased nocturnal voiding. Pain was associated with a substantial increase in nocturia after adjusting for age and somatic and mental health. Sick-leave was more common in association with more nocturnal voids.