A series of forty patients of maturity onset diabetics was selected. Their body constitution was decided as Vataja (V), Pittaja (P) and Kaphaja (K) on the basis of physical, Psychic and socio-economic features as described in Ayurvedic classics. These groups were also supported by objective findings i.e., Aathropometric and Biochemical. In V ponderal index was found to be maximum (45.13 ± 3.28) with minimum body surface area (1.46 ± 0.15 sq. metre) along with acetylcholine level (1.1 ± 0.54 μg/ml) in blood. On contrary in K body surface are was maximum (1.625 ± 0.119 sq. metre) with minimum ponderal index (41.64 ± 5.43). Acetylcholine was lower (0.94 ± 0.38 μg/ml) and blood histamine was highest (0.160 ± 0.041 μg/ml) in this group. In P plasma catecholamines were observed to be highest (16.39 ± 8.55 μg/ml) and the physical findings were medium. Respectively in diabetics of V,P,K constitution the hyperglycemia was observed to be sever (256 ± 126.99 mg%) moderate (189.09 ± 94.49 mg%) and mild (173.77 ± 68.43 mg%). Correspondingly, plasma insulin was found to be lowest in P (9.15 ± 5.22 μu/ml) but was highest in K (18.44 ± 10.70 μu/ml).When these patients were further divided into two groups on the basis of duration of illness i.e <5 years and >5years. It was observed that deterioration in glucose tolerance and fall in plasma insulin level was maximum in the patients of V constitution, minimum in K and medium in P. Thus the role of the body constitution, in the progression of diabetes assumes vital importance.