Systemic capillary leak syndrome is a rare, severe disorder with a high mortality rate. It consists of the shift of fluid and proteins from the intravascular to the extravascular compartment with subsequent hypovolemic shock. We describe a 34-year-old-woman who had several episodes of generalized edema that evolved to hypovolemic shock. During the acute phase, laboratory investigations revealed marked hypoproteinemia, leukocytosis, and high levels of hematocrit and hemoglobin. A paraprotein IgG kappa chain was detected. Although different therapeutic trials were used, the patient continued to have similar episodes and she died during an acute episode 2 1/2 years after the first symptom of this disorder. The cause of systemic capillary leak syndrome is unknown. The presence of a paraprotein IgG is frequent in this group of patients.