Eosinophilic fasciitis (EF) is a rare disorder of unknown etiology characterized by eosinophilia, indurations of the skin, and inflammation of the fascia. Magnetic resonance imaging (MRI) has been used to assist the diagnosis and to monitor the response to treatment, and the commonly used therapy has been corticosteroids. However, the use of ultrasonography (US) in the diagnosis and the management of EF has not been reported previously in Korea. In addition, the effects of methotrexate (MTX) treatment have rarely been reported in corticosteroid-resistant patients with EF. Here, we describe two cases of EF resistant to corticosteroid therapy alone where the combination of MTX and corticosteroids was effective. Furthermore, we show that US is useful modality in supporting the clinical diagnosis and monitoring the response to treatment of patients with EF.