The activity of red blood cell Glucose 6-phosphate dehydrogenase (G6PD) in one hundred and twenty six healthy male individuals who are Nigerians residing in Jos was evaluated. The enzyme activity was determined quantitatively by spectrophotometer assay method. The activity of red cell G6PD enzyme was subnormal in 20 % of the population studied. This agrees with previous report of the prevalence of G6PD deficiency in Nigerian males from the Western region of the country which is between 20 and 26 %of the population. The proportion of Nigerian males with subnormal G6PD activity is relatively constant irrespective of their geographical location.