Systemic capillary leak syndrome (SCLS) is a disorder characterized by increased vascular permeability with intermittent acute episodes of profound capillary leak that may result in hypotension or shock. A rarely described chronic form of SCLS (cSCLS) presents as refractory edema, with pleural and/or pericardial effusions and hypoalbuminemia. These entities are differentiated by massive and periodic episodes of capillary leak, which can result in shock in SCLS, and chronic refractory edema in cSCLS. The etiologies of these disorders are poorly understood, but both acute and chronic forms often present with an associated monoclonal gammopathy. Flares of the SCLS have been reduced by treatment with intravenous immune globulin (IVIG). Only six cases of cSCLS have been reported, and previous treatments have included steroids, terbutaline, and theophylline. Based upon the reported responses of SCLS to IVIG, we present the case of a 54-year-old man with cSCLS where ongoing treatment with IVIG resulted in a marked and sustained improvement in the signs and symptoms of the capillary leak syndrome. .