This research was carried out to determine the influence of diets containing Vernonia amygdalina leaves on body and organ weights, glycosylated and insulin concentrations of streptozotocin- induced diabetic Wistar rats. Fifty albino wistarrat were divided into five groups with ten rats in each group. Group 1 and group 2 (normal and diabetic control respectively) were fed with control diet. Group 3 and group 4 (diabetic ) were fed with diet containing Vernonia amygdalina leaves at 5% and 7.5%, respectively. Group 5 (diabetic) was fed with control diet and administered insulin. The experiment lasted for 28 days. Initial and final body weights, weight of some organs and tissues, and feed consumption were taken and noted. Glycosylated hemoglobin, and insulin concentrations were determined using standard methods. Results showed that diabetic control rats had significant reduction (p<0.05) in body weight compared to the normal control after the 28 days. Diabetic rats consuming Vernonia amygdalina diets had significant (p<0.05) increase in body weight compared to the diabetic control. Weight gained by diabetic rat consuming Vernoniaamygadalina diets were significantly (p<0.05) lower compared to diabetic rats receving insulin and not significantly different (p>0.05) compared to the normal control. Average daily feed intake were similar except for the group on insulin. This shows that diets containing leaves of Vernonia amygdalina help the diabetic rats to gain normal weight but insulin made the diabetic rats to gain excessive weight. Diets and insulin restored the size of the liver and kidneys affected by diabetes mellitus. There was a significant reduction (p<0.05) in the amount of fat deposited in the abdomen of rats with diets compared to those with insulin. Significant decrease (p<0.05) was obtained for the concentration of glycated hemoglobin while significant increase (p<0.05) was obtained for insulin groups concentration for the diets and insulin but the reverse was obtained for the diabetic control. It was concluded that diets containing Vernoniaamygadlina leaves are potential antidiabtic agents with no adverse consequences on body weight in rats.