Modern double beam laser technique allows screening for hereditary spherocytosis in the course of routine hematology. An incidence of 1:150 men and 1:800 women has been determined. The anomaly is symptomless in the majority of the cases. This explains the discrepancy between our values and the incidence of 1:5,000 reported in the literature. The diagnosis of hereditary spherocytosis should be reported to the physician and the patient, as it may be wayleading in case of unexpected, unspecific complications such as anemia, jaundice, cholelithiasis, liver cell damage and iron overload. Regular monitoring of plasma ferritin and glucose is recommended.