Back pain is one of the most common complaints in the general population and chronic back pain is a major Public Health burden. However, the prevalence of chronic back pain in Germany is not known. The aim of our study was to determine the prevalence of chronic back pain in the general adult population in Germany and to identify highly affected population groups. A nation-wide computer-assisted telephone interview (CATI) survey was conducted with 8,318 men and women aged 18 years and older residing in German households. Participants were selected using the Gabler-Häder telephone sampling method and the next-birthday method. The one-year prevalence of chronic back pain defined as daily or almost daily back pain over a period of three months was 16 % in men and 22 % in women, the lifetime prevalence 24 % in men and 30 % in women. The 12-months prevalence of any back pain was 66 % in women and 58 % in men. Back pain on the day preceding the interview was reported by 18 % of men and 27 % of women and had a median intensity on a 1 - 10 point scale of 5 in women and 4 in men. Factors independently associated with chronic back pain in the past 12 months were age, female sex, a history of arthritis, self-reported depression, lower educational level, current unemployment, overweight or obesity, no sports, smoking and living with a partner. In conclusion, chronic back pain is a highly prevalent complaint in the general population in Germany. The association not only with bone and joint diseases but also with depression, a lower level of education and with certain lifestyle behaviours emphasises that back pain should not be viewed only in the context of the spine.