Ascites is a rare complication of multiple myeloma and may occur either at presentation or more often during the disease course. Most reported cases have been associated with IgA type of myeloma. When it occurs, it is usually associated with extensive liver infiltration with plasma cells, infectious peritonitis or myelomatous peritoneal infiltration. Herein, we describe a case of IgG type multiple myeloma diagnosed by further examinations due to the presence of plasma cells in ascitic fluid.