Hemoglobin and DNA gene analyses were carried out in two Black Canadian families. In Family Q, both the parents and the brother were found to be heterozygotes for alpha-thalassemia-2 with the following alpha-genotypes: -alpha 3.7/alpha alpha, -alpha 4.2/alpha alpha and -alpha 4.2/alpha alpha, respectively. In Family C, the mother was found to be a homozygote for alpha-thalassemia-2 with the alpha-genotype of -alpha 3.7/-alpha 3.7. In both families, the propositi were compound heterozygotes for alpha-thalassemia-2 with the alpha-genotype of -alpha 3.7/-alpha 4.2. The propositus in Family C was also a sickle cell trait carrier. The usefulness of DNA gene analyses in family studies of hemoglobinopathy was discussed.