Cord blood samples from 29,611 infants born in Los Angeles over a 7 1/2 year period were examined for hemoglobinopathies. Among 4,134 Black newborns, the frequency of sickle cell anemia (SS) was 0.3 per cent of sickle cell trait (AS) 8 per cent, and of Hb-C trait (AC) 2 per cent, Of 17,781 Spanish surnamed (Mexican) newborn, 0.5 per cent had sickle cell trait, and 0.1 per cent had Hb-C trait. Of the 5,541 Caucasian infants, 0.7 per cent had sickle cell trait, and 0.15 per cent had Hb-C trait. Twenty-three Black children with major hemoglobinopathies included 16 with sickle cell anemia, two with hemoglobin C disease (CC), and five with SC disease. [ABSTRACT FROM AUTHOR]