We asked the question, is the haplotype found with the sickle hemoglobin gene associated with different hematological characteristics in patients who were combined heterozygotes for sickle hemoglobin and hemoglobin C (Hb SC disease)? In 73 adults with Hb SC disease, a Benin haplotype chromosome was present in 56%, and Bantu (or Central African Republic; CAR), Senegal, and atypical haplotype chromosomes were found in 25%, 6%, and 12%, respectively. No significant difference were found in hematological characteristics or fetal hemoglobin levels of patients with Benin/C, CAR/C, Senegal/C, and atypical/C haplotypes. There were 71% C I, 18% C II, and 11% other beta(c) haplotypes. Fetal hemoglobin levels are lower in Hb SC disease than in sickle-cell anemia. Perhaps because haplotype has no discernible effect on fetal hemoglobin level in Hb SC disease, it does not modulate its hematological features.