Abstract: This study was designed to investigate the biochemical and histomorphological changes occurring due to streptozotocin-induced diabetes mellitus in rabbits. Twelve New Zealand male rabbits of uniform age were divided into two Groups. Group I was made diabetic by single intravenous injection of streptozotocin (@ 65mg/kg.b.w.) whereas Group II served as control. Significant increase in blood sugar (P<0.01), blood urea (P<0.10) and serum creatinine (P<0.10) was recorded in Group I rabbits compared to Group II rabbits. Further, histomorphological alterations of pancreas, kidneys, liver, heart, lungs and brain were observed. However, no pathological features were observed in alimentary canal. From the study, it is concluded that streptozotocin-induced diabetes causes disturbances in biochemical and histological features in rabbits and serves as a model in studying the various complications arising due to this illness.