Sweet syndrome is characterized by acute onset of fever. neutrophilic leukocytosis, painful erythematous plaque on the face and extremities, infiltration of mature neutrophils in the dermis. Cutaneous lesion and clinical symptoms rapidly improve after treatment with systemic corticosteroids. The cause of sweet syndrome is unknown but the associations with hypersensitivity to bacteria, virus, or tumor antigen have been reported. Sweet syndrome itself can be a premonitory manifestation of malignancy, so diagnostic work up for other internal malignancy is recommended. Because of fever and leukocytosis, cutaneous infections are important differentials. Sweet syndrome can be divided into 4 categories according to associated disease and symptom. (Idiopathic Sweet syndrome, Parainflammatory Sweet syndrome, Paraneoplastic Sweet syndrome, Pregnacy associated Sweet syndrome.) Sweet syndrome is relatively rare disease and the association with myelodisplastic syndrome has been reported. We report a case of Sweet syndrome associated with myelodisplastic syndrome which has initial manifestation of odontogenic buccal cellulites.