Summary Two cases of agammaglobulinemia in the adult are presented. In the fir-1 case there was hepatosplenomegaly, thrombocytopenia, leucopenia and an acute hemolytic syndrome (Lederer anaemia). The patient run a high fever for several months, but no infectious focus was found and all hemocultures remained sterile. Despite all kinds of treatment and substitution this patient died. In the second case the diagnosis was suspected because of the history of repeated lung infections since the age of 7. The patient underwent a lobectomv previously. He was admitted with a purulent pericarditis (staphylococcus albus). After drainage of the pericarditis the patient responded well to antibiotics. He receives now monthly injections of human plasma in an effort to correct his deficiency and prevent further infectious episodes.