To investigate daytime sleepiness and napping in relation to age, health and nocturnal sleep. An epidemiological survey by means of a questionnaire. The counties of Västerbotten and Norrbotten in northern Sweden. All 10,216 members of the pensioners' association SPF. Daytime sleep, daytime sleepiness, health, night sleep, somatic diseases and medication. Daytime sleepiness was 4.9 (3.7-6.4) and 5.1 (4.2-6.1) times more common in men and women, respectively, in poor health than in those in good health. It was also more common in subjects suffering from cardiac diseases, diabetes and musculo-skeletal diseases, urological symptoms, and diseases with sensory and neurological impairments, compared with symptomless subjects. Stepwise regression analysis showed an increase in daytime sleepiness in men in association with impaired general health (r2 = 0.067), frequent awakenings (r2 = 0.098), higher age (r2 = 0.109) and difficulty in falling asleep again after nocturnal awakening (r2 = 0.115), and in the women, in association with impaired health (r2 = 0.118), difficulty in falling asleep again (r2 = 0.149), frequent awakenings (r2 = 0.160) and higher age (r2 = 0.171). There was no further increase in r2 = either for men or women in relation to use of hypnotics. Age, poor health and different somatic diseases, but not hypnotics, are associated with daytime sleepiness in elderly persons.