This study was conducted on 823 male and female subjects to determine the frequency of glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and sickle cell gene in Al-Qunfuda, a densely populated and malaria endemic region in western Saudi Arabia. The results show the presence of both sickle cell and G-6-PD deficiency genes in this population. The prevalence of Hb S heterozygotes in the total population was 18.93% and that of homozygotes was 2.02%. The gene frequency of sickle cell gene was 0.121. G-6-PD-B+ was the normal enzyme and occurred at a frequency of 83.60% and 78.46% in the male and female population, respectively. G-6-PD variants identified included G-6-PD Mediterranean, G-6-PD-A+, G-6-PD-A- and G-6-PD-Mediterranean-like. The frequency of each variant in the male and female population was 10.65% and 9.74% for G-6-PD-Mediterranean, 2.30% and 1.53% for G-6-PD-A+, 0.46% and 0.51% for G-6-PD-A- and 3.0% and 9.74% for the G-6-PD-Mediterranean-like variants, respectively. No significant interaction between sickle cell and G-6-PD genes could be demonstrated.