The present study, a questionnaire survey, was undertaken to assess the influence of somatic health, mental health, pain and age on sleep in a group of men and women. The survey comprised 1948 randomly selected persons (47.7% men) of ages 20-64 years. Poor somatic health was reported by 12.5% of the men and 15.3% of the women and poor mental health by 8.7% of the men and 10.6% of the women. Among the men very good sleep was reported by 34.7% and rather good, rather poor and very poor sleep by 52.8%, 10.9%, and 1.6%, respectively. The corresponding frequencies in women were 32.7%, 51.9%, 12.9% and 2.5%, respectively (NS). No or very light pain was reported by 50.7% of the men and rather light, rather severe or very severe pain by 35.7%, 12.0%, and 1.6%, respectively. The corresponding frequencies in women were 48.1%, 35.4%, 14.1% and 2.4%, respectively (NS). A forward stepwise regression analysis showed that in men, more severe sleep disturbances were associated with poorer mental health (R2=0.227), pain (R2=0.292) and poorer somatic health (R2=0.304). Correspondingly, more severe sleep disturbances were associated with poorer somatic health (R2 = 0.218), poorer mental health (R2=0.280) and pain (R2=0.326) in women. Age, education, being gainfully employed and income were deleted by the regression model in both sexes. It is concluded that poor mental health exerts the most detrimental influence on sleep in men, somatic health in women, and that age does not independently affect sleep at all.