Blood samples from Tehran and Isfahan were examined for seven red cell enzyme systems. Polymorphic variations was present for acid phosphatase, phosphoglucomutase locus I, adenylate kinase, 6-phosphogluconate dehydrogenase and phosphohexose isomerase loci controlling red cell enzyme systems. Statistical analysis demonstrated no significant variation between the two Iranian samples. Gene frequencies were compared with the distribution pattern known in other Iranian populations. The lactate dehydrogenase and Malate dehydrogenase systems were monomorphic.