A total of 1,582 subjects from 10 villages of different ethnic populations were screened for glucose-6-phosphate dehydrogenase (G6PD) deficiency (GdB-, Mediterranean variant) and hemoglobin S gene, and the coincidence of both abnormalities was determined. Although the prevalence of both abnormalities was found to be highest in an Eti-Turk group living in the Tarsus area, coincidence was not significant. In a single village of Adana Eti-Turks, however, coincidence was found to be significant, although neither the frequency of G6PD deficiency nor the existence of hemoglobin S gene was highest in that village.