We have examined the molecular basis of three inherited hemoglobin (Hb) disorders present in a Czechoslovakian girl with a severe, transfusion-dependent, hemolytic anemia. She is heterozygous for Hb E (on a genetic background specific for Czechoslovakian families), heterozygous for the beta zero-thalassemia (thal) allele IVS-I-1 (G----A), and heterozygous for an alpha-globin gene triplication. The combination of these three undesirable traits results in a severe chain imbalance that is the basis of the serious hemolytic disorder observed in this teenager.