Of the 721 documented patients in the German Registry for Adamantiades-Behçet disease (registered charity), 258 were of German and 308 of Turkish descent, along with 30 other countries of origin. The prevalence in Germany is 0.9:100,000. Manifestation of the disease was predominantly in the third decade of life (median age: 26.5 years) and in 10.7% the disease onset was under 16 years of age. The full clinical picture developed on average in 2.9 years (median 3 months). Patients of Turkish descent showed androtopism in contrast to those of German descent (female:male 1.9:1), which was also detected in the whole collective in a ratio of 1.4:1. In 12.4% there was a family history with differences between German and Turkish patients (3.8% versus 14.6%) as well as in patients with disease onset in young and adult age (25.0% versus 7.3%). Most frequent features included oral aphthae (98.5%), cutaneous lesions (81%), genital ulcers (64.7%), ocular manifestations (51.6%), arthritis (52.4%) and positive pathergy test (30.8%). Turkish patients suffered significantly more often from eye manifestations compared with Germans, while in German patients prostatitis/epididymitis and gastrointestinal involvement were more frequently documented. As serious complications arose blindness 6.8%, meningoencephalitis 4.0%, severe arthritis 2.6%, fatal outcome 1.2%, hemoptysis 1.1% and gastrointestinal perforation 0.5%. The HLA-B5 antigen was positive in 58.1% and showed an association with eye manifestations. The relative risk of HLA-B5 positive individuals is high in both Germans (6.57) and Turks (5.81).