DEGS1-MH is part of the first wave of the German Health Interview and Examination Survey (DEGS1) covering all relevant health issues. Aims of DEGS1-MH are to supplement DEGS1 by describing (1) the distribution and frequency, the severity and the impairments of a wide range of mental disorders, (2) risk factors as well as patterns of help-seeking and health care utilization, and (3) associations between mental and somatic disorders, (4) and by comparisons with a similar survey in the late 1990s (GHS-MHS), longitudinal trends and changes in morbidity over time. Out of all eligible DEGS1 respondents (nationally representative sample aged 18-79), N = 5318 subjects (conditional response rate 88%) were examined at their place of residence by clinically trained interviewers with a modified version of the standardized, computer-assisted Composite International Diagnostic Interview (DEGS-CIDI). Innovative additions were: a comprehensive neuropsychological examination, a broader assessment of psychosis-like experiences, disorder-specific disabilities, help-seeking and health care utilization. The mental health module and its combination with the assessment of somatic and other health issues in DEGS1 allow for internationally unique, detailed and comprehensive analyses about mental disorders and the association of mental and somatic health issues in the community, constituting an improved basis for regular future surveys of this sort.