The diagnosis of beta-thalassemia (beta-that) trait is usually based on an elevated HbA(2) fraction (3.5% to 8%). Co-inheritance of a delta-globin variant along with beta-globin gene defects can interfere with the diagnosis of beta-that trait by causing normal HbA(2) levels. In this report, we present an infant with beta-that major whose mother's beta-that trait was missed twice before due to an accompanying delta-globin mutation (HbA(2)-Yialousa. HBD: c.82G > T). resulting in a borderline HbA(2) level. In an individual with microcytosis and hypochromia but an apparently normal HbA(2) level, compound heterozygosity for a delta-globin mutation and a beta-that mutation should be remembered in the differential diagnosis.