The German federal states initiated the ‘Pathological Gambling and Epidemiology’ (PAGE) program to evaluate the public health relevance of pathological gambling. The aim of PAGE was to estimate the prevalence of pathological gambling and cover the heterogenic presentation in the population with respect to comorbid substance use and mental disorders, risk and protective factors, course aspects, treatment utilization, triggering and maintenance factors of remission, and biological markers. This paper describes the methodological details of the study and reports basic prevalence data. Two sampling frames (landline and mobile telephone numbers) were used to generate a random sample from the general population consisting of 15,023 individuals (ages 14 to 64) completing a telephone interview. Additionally, high-risk populations have been approached in gambling locations, via media announcements, outpatient addiction services, debt counselors, probation assistants, self-help groups and specialized inpatient treatment facilities. The assessment included two steps: (1) a diagnostic interview comprising the gambling section of the Composite International Diagnostic Interview (CIDI) for case finding; (2) an in-depth clinical interview with participants reporting gambling problems. The in-depth clinical interview was completed by 594 participants, who were recruited from the general or high-risk populations. The program provides a rich epidemiological database which is available as a scientific use file.