Diabetes mellitus is a heterogeneous group of metabolic syndromes characterized by an elevation of blood glucose caused by a relative or absolute deficiency of insulin. The incidence of diabetes is growing rapidly worldwide. Drug treatment for diabetes mellitus is expensive and carries risks for many adverse effects. India is one among rich sources of medicinal plants useful in the treatment of diabetes. The study was performed to investigate the blood glucose lowering effect of Naringi crenulata leaves in experimentally induced diabetic rats. Administration of Hexane extract of N. crenulata leaves produced significant change in the blood glucose level as compared to control. Histological examination of pancreas showed destruction of beta cells in Islets of pancreas in group-C whereas retaining of islets and few degranulations of beta cells of pancreas found in group- D. These observations and results provide information that hexane extract of N. crenulata leaves has hypoglycaemic effect in experimentally induced diabetic rats which requires further investigation.