A 30 years man presented with fever and skin manifestations in the form of multiple tender, erythematous, asymmetric nodules and papules predominantly over the upper arms and back. The nodules were coalescing to form irregular sharply demarcated plaques over the forearms and thighs. There were pustules over the nodules. He also had tendoachilles tendinitis. The total leucocyte count, differential count and skin biopsy confirmed the diagnosis of Sweet's syndrome (acute febrile neutrophilic dermatosis). This patient, a case of Idiopathic Sweet's syndrome with tendoachilles tendinitis responded to oral corticosteroids.