We here report the phenotypes and genotypes of 63 patients of North African origin, carriers of Hb Groene Hart [Hb GH, α119(H2)Pro → Ser; HBA1: c.358C>T], an α(+)-thalassemia (α(+)-thal) hemoglobin (Hb) variant. Fifty patients were heterozygous, five were homozygous and eight also carried the common -α(3.7) (rightward) deletion in compound heterozygosity. The expression of the α(GH)-globin chain is increased in the following order: heterozygous, compound heterozygous and homozygous. Parallel significant changes of mean corpuscular Hb (MCH) and mean corpuscular volume (MCV) were also observed. Our large cohort of Hb GH carriers could have been obtained by the systematic realization of globin chain separation by reversed phase liquid chromatography (RP-LC) in our routine Hb testing.