This study aims to explore the relationship between naps, sleep/wake schedule, sleep symptoms, sleep and mental disorders in a representative sample of the noninstitutionalized German population composed of 2216 women and 1899 men aged 15- 99 years. A telephone interview survey was performed by lay interviewers using the Sleep-Eval software. Napping on at least 2 days per week was cited by 22.2% (95% confidence interval: 20.9% to 23.5%) of the sample and increased linearily with age, reaching 53.3% in subjects 75 years of age and over. Presence of daytime sleepiness was positively associated with napping for all age groups. In subjects younger than 65 years, napping was also related to night or shift working, presence of a physical illness, bipolar disorder, and idiopathic hypersomnia. In elderly subjects (>= 75 years), only the report of daytime sleepiness and primary snoring were related to napping. In the general population, the presence of napping in the younger age groups (<65 years) appears mostly to be the consequence of lifestyle such as night or shift working and/or of a mental or sleep pathology, whereas in the elderly, it is partly explained by disruptive events occurring at night, namely, nocturnal awakenings, sleep disorders affecting legs, and primary snoring.