POEMS syndrome is a rare clonal plasma cell disorder without standard treatment. Based on the efficacy and low toxicity of a combination of melphalan and dexamethasone (MDex) for light chain amyloidosis, we conducted a prospective study of MDex treatment for patients with newly diagnosed POEMS syndrome. Thirty-one patients (19 men) were enrolled and the median age at the time of diagnosis was 44 years (range, 32-68 years). All patients received 12 cycles of MDex treatment. Twenty-five patients (80.6%) achieved hematologic response including 12 (38.7%) complete remission and 13 (41.9%) partial remission. Of all 31 patients, the neurologic response rate was 100%, assessed by overall neuropathy limitation scale (ONLS). The initial neurologic response was observed in 24 patients (77.4%) at 3 months after treatment and the median time to maximal neurologic response was 12 months (range, 3-15 months). Moreover, MDex substantially improved the level of serum vascular endothelial growth factor and relieved organomegaly, extravascular volume overload, and pulmonary hypertension. Only 6 patients (19.3%) suffered from grade 3 adverse events during treatment. All patients are alive and free of neurologic relapse after the median follow-up time of 21 months. Therefore, MDex is an effective and well-tolerated treatment option for patients with newly diagnosed POEMS syndrome.