Three different hemoglobinopathies, i.e. Hb S, Hb Chad [α23 (B4)Glu→Lys], andα-thalassemia-2 (−3.7) have been observed in eight members of a family from Surinam. The proposita had all three abnormalities, while her mother and four of her half-brothers had Hb Chad together with anα-thalassemia-2 heterozygosity or homozygosity. Gene mapping and dot-blot analysis of amplified DNA identified a G→A mutation in codon 23 of theα2αl hybrid gene resulting in the Glu→Lys substitution. The quantity of theα-Chad chain averaged 31.5% in its carriers with an additionalα-thalassemia-2 heterozygosity [-αCnad(−3.7 kb)/αα], and 43% in the two carriers with an additionalα-thalassemia-2 homozygosity [-αChad(−3.7 kb)/-α(3.7 kb)]. These quantities are considerably higher than those reported for families from Chad, China, and Japan; the low levels of 14.5-24% Hb Chad in members of previously reported cases suggest a mutation on a chromosome with twoα-globin genes [ααChad/ααorαChadα/αα].