Sweet's syndrome (SS) has been reported as an association with malignant neoplasms and autoimmune diseases, e.g., Behçet's disease, Sjogren's syndrome, and rheumatoid arthritis. But dermatomyositis (DM), one of the rare autoimmune diseases, was not reported as an associated disease of SS. We describe an interesting case of SS associated with DM. Diagnosis was made by skin biopsy, and subsequent clinical resolution occurred after institution of prednisolone.