In view of World Health Organization (WHO) recommendation on the use of medicinal plants for the management of diabetes mellitus, this study evaluated the effect of ethanolic leaf extract of Vinca major L. on biochemical parameters and glucose level of alloxan induced diabetic rats as objective. Sixty-four male Wistar albino rats were induced with diabetes by a single intraperitoneal injection and were separated into four groups (1-4) of sixteen rats each. Group 1 served as the control while groups 2 to 4 served as the test groups. Apart from the control, the test groups were treated with different concentrations of the leaf extract, and four rats from each group were sacrificed every seven days for assessment. The treatment period lasted for 28 days. Haemoglobin (Hb) levels in groups 3 and 4 rats significantly increased (p<0.05) against the control throughout the number of days of the study. Red blood cell (RBC) levels in groups 2 and 4 increased significantly (p<0.05) against the control on the 14 th day, while all the test group rats had significantly increased (p<0.05) RBC levels on the 21 st and 28 th days of the study. The observed trend followed by electrolyte ions, urea and creatinine in test rats against the control in the present study, may be attributed to V. major leaf extract trying to salvage the excretory organs of alloxan battered diabetic rats. Glucose level, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) liver enzymes reduced significantly (p<0.05) in test rats against the control. Diabetic rats treated with V. major leaf extract in this study, showed significant improvements on those associate problems of diabetes which include anaemia, dyslipidaemia, and hepatic necrosis and inflammation. Rats treated with the leaf extract also showed reduced glucose level (Hypoglycemia). From the observations of this study, extract from leaf of V. major may be effective against diabetes and some of its associate problems.