Systemic capillary leak syndrome (SCLS) is a rare disorder of unknown etiology, characterized by recurrent hypovolemic shock attacks associated in most cases with a serum monoclonal immunoglobulin. Prophylactic therapy is usually disappointing and the outcome is often fatal. We report on a patient with recurrent hypovolemic shocks consistent with the diagnosis of SCLS associated with severe serum panhypogammaglobulinemia but no detectable monoclonal immunoglobulin or B cell proliferation. Attacks were often preceded by severe respiratory infections. Both infections and attacks were successfully prevented by i.v. gammaglobulin replacement. Further evaluation is needed to assess the efficacy of i.v. gammaglobulins in patients with SCLS but without hypogammaglobulinemia.