Background. Behçet's disease is a chronic, relapsing disease, about which information on its clinical course in juveniles is only available from small groups of patients. Materials and Methods. Patients suffering from Behçet's disease who had their first lesion at or before the age of 16 were evaluated in terms of: age at onset, mucocutaneous signs, and findings related to systemic involvement. Ninety‐five patients, evaluated as having juvenile Behçet's disease (JBD), were detected among 1784 Turkish Behçet's patients. The mean age of these 95 patients (51 boys or men, 44 girls or women) who had JBD was 26.8 ± 7.1 years. Results. The difference between sexes in terms of age at onset, development period of second lesions, and systemic involvement was not found to be significant in JBD. Patients were divided into two groups, one showing severe disease (N = 27) and the other mild disease (N = 68). There was no significant difference between the two groups with respect to age, age at onset, and sex distribution. The interval between the development of the first and second lesions was shorter in the patient group with severe disease (P < 0.001) and the development of second lesion was most frequently seen in the first 5 years (P < 0.05). Systemic involvement developed also in a shorter time in the group with the severe disease (P < 0.01) and was most frequently encountered during the first 5 years (P < 0.05). Conversely, patients with the mild disease developed systemic involvement more frequently after 6 years or later. Conclusions. Severe Behçet's disease in children and juveniles shows no age or sex predilection, but leads to an earlier recurrence and more severe systemic signs than the mild form.