SummaryComplete and permanent absence of peripheral eosinophilic granulocytes was observed in a patient also presenting with total myeloperoxidase deficiency. The anomaly was suspected because of complete absence of the eosinophilic cluster in the display of a H*3 Technicon hematological automate and was confirmed by traditional staining of more than 100.000 leukocytes. A severe infectious problem during adolescence could be related to MPO deficiencyn this patient. No specific disorder attributable to aneosinophilia was however observed subsequently.