A 27-year-old male patient presented with new thrombotic areas and undiagnosed partially old thrombosis of both vena femoralis, vena iliaca externa, vena iliaca communis and the vena cava inferior. He reported episodes of orchitis, recurrent oral aphthous ulcers, mild arthritis of several joints, recurrent iridocyclitis and occasionally skin pustules. The diagnosis of Adamantiades-Behçet's disease was corroborated by a positive pathergy test. Already in 1946, Benediktos Adamantiades described vascular thrombosis and later included it to his diagnostic criteria as the fourth cardinal sign of the disease. Small and large vessels in almost all organs may be affected. Vein thrombosis, especially at the extremities, represents the most frequent vascular manifestation of the disease. Conservative treatment is essential at the acute phase, since surgical intervention can be associated with vessel reocclusion or lethal course of the disease. Oral prednisolone and chlorambucil as well as phenprocoumon for 15 months stabilized the signs of our patient. Recanalization of the vessels was observed. Interferon-alpha monotherapy was subsequently administered. During the 52-month follow-up single oral aphthous ulcers were occasionally observed and erythema nodosum-like lesions and skin pustules occurred at the lower extremities two weeks after a temporary discontinuation of treatment.