A systematic examination of 2,257 Congolese newborns from Brazzaville for abnormal hemoglobins has been conducted. Gene frequency for HbS was 0.117; no HbC was found. Of the sample 14.4% had detectable amounts of Hb Bart's. Beta-thalassemia trait frequency was approximately estimated to 0.3%, 5 mutations of gamma chain, and 1 mutation for alpha chain were detected.