Behcet's disease (BD) is a systemic vasculitis of unknown aetiology, characterized by relapsing episodes of oral aphtous ulcers, genital ulcers, ocular lesions and skin lesions. Sweet's Syndrome is characterized by fever, neutrophilia, tender erythematous skin lesions, and histopathologic evidence of a dense neutrophilic infiltration in the papillary dermis without vasculitis and it is one of the less common skin lesions of Behcet's disease. We present a case of 44-year old woman with Behcet's disease who had erythematous and painful eruptions on her hands and forearms. She had been diagnosed as Behcet's disease after oral aphtous ulcers, genital ulcers and positive pathergy test seven years previously. An incisional biopsy of an erythematous lesion involving the forearm and laboratory work-up were performed. Based on history, clinical findings, laboratory data and histopathological examination, the patient was diagnosed as Sweet's Syndrome. Behcet's disease may manifest Sweet's Syndrome a long-time after its onset even in the absence of cardinal symptoms.