In Colorado, newborn screening for hemoglobinopathies by cellulose acetate and citrate agar electrophoresis of dried capillary blood spots was established in 1979. We reviewed the results of screening 528,711 infants through 1988. Forty-seven infants with sickle cell diseases and 27 infants with other hemoglobin diseases were identified. The initial screening failed to detect sickle cell anemia in 4 infants, but the hemoglobinopathy in 3 of these infants was diagnosed correctly by routine retesting of those with suspected sickle cell trait. A total of 47 infants with sickle cell diseases were followed through September 1989. There was no mortality among these infants. The screening test identified 3779 infants (1:140 births) with a suspected hemoglobin trait; confirmatory retesting was obtained in 53%. The results of our experience confirm the value of newborn screening for hemoglobinopathies but suggest that a more sensitive test would improve the program.