Recently, a polymorphism in the glycogen synthase gene was shown to be associated with the development of non-insulin dependent diabetes mellitus (NIDDM) and identified patients with a strong family history of diabetes and hypertension in the Finnish population. However, no association was found in French and Japanese populations. We investigated the possible association between the Xbal polymorphism of the glycogen synthase gene and NIDDM in the Russian population. One hundred fifty NIDDM patients and 109 healthy controls were studied. In 16 of 150 Russian NIDDM patients (10.7%), the Xbal polymorphism was found, and 17 of 109 controls (15.6%) showed the Xbal polymorphism (P > .05). These results suggest that the Xbal polymorphism of the glycogen synthase gene cannot be used as a marker for NIDDM in the Russian population.