Multiple myeloma (MM) is a neoplastic proliferation of plasma cells with overproduction of monoclonal immunoglobulins and infiltration into the bone and other organs. Ascites can develop in patients with lymphoproliferative and solid malignancies involving the peritoneum. However, ascites is unusual in MM and rarely the initial presenting sign or symptom. The development of ascites can be due to peritoneal infiltration or secondary to hepatic involvement, heart failure, or kidney failure. Ascites in MM reflects a more aggressive stage, and the reported prognosis is poor, with a median survival of 1-2 months. Here we present a rare case of immunoglobulin A lambda MM presenting with massive myelomatous ascites.