Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked genetic disorder characterized by low levels of the G6PD enzyme. It is present worldwide but with more prevalence in the Middle East and the Mediterranean areas. We report a case of severe hemolysis due to G6PD deficiency manifesting as methemoglobinemia in a 70 year old Omani male never known to have any previous hemolytic episodes or previously diagnosed of G6PD deficiency.