To evaluate the prevalence of the clinical findings in Behçet's disease, we retrospectively analyzed the clinical data of 2147 Behçet patients from 9 to 87 years of age (mean age 38.3 years) followed up during the years 1976 through 1997. One thousand ninety three patients were male and 1054 patients were female. The male/female ratio was 1.03. The mean age at onset was 25.6 years. A family history of Behçet's disease was present in 7.3% of the patients. Positive pathergy was found in 1220 (56.8%) patients. All of the patients had mucocutaneous lesions. Out of the 2147 patients the disease manifested itself as only mucocutaneous involvement in 1168 patients. The prevalence of systemic manifestations was found as follows: 28.9% ocular involvement, 16.0% musculoskeletal involvement, 16.8% vascular involvement, 2.8% gastrointestinal involvement, 2.2% neurological involvement. Pulmonary involvement was seen in 20 (1.0%) patients, cardiac involvement was seen in 3 patients and renal involvement was observed in 2 patients. Male patients had vascular involvement 5.02, neurologic involvement 2.21 and ocular involvement 1.98 times more frequently than female patients.