Introduction: Diabetes mellitus is associated with a wide range of kidney and liver disorders. The aim of this study was to compare the effect of alcoholic extract of aerial parts of Melissa officinalis on indicators of liver function and kidney in diabetic rats. Materials and Methods: Thirty-five wistar rats were divided into 5 groups (n=7 each) as follows: Control, diabetic control and three diabetic groups, which received alcoholic extract of Melissa officinalis at doses of 100, 200 mg/kg body weight respectively through gastric gavage and glibenclamide 10 mg/ kg, for a period of 3 weeks. Diabetes was induced by streptozotocin (STZ). At the end of this period (21 days), blood samples were collected for measurement of liver enzymes and factors for data analysis. Results: Amounts of enzyme levels of alanine transaminase (ALT) and aspartate aminotran­sferase (AST) in the group treated with the extract, compared to the diabetic control group showed no significant changes, whereas serum levels of alkaline phosphatase (ALP) and gamma glutamyl transferase (GGT) were significantly reduced (P<0.05), which declined most in the group receiving the minimum dose of the extract. Serum creatinine and urea in the group receiving the highest dose showed a significant decrease compared to other groups (P<0.05). Conclusion: The extract Melissa officinalis with lower levels of liver enzymes, particularly ALP and GGT and renal markers, urea and creatinine was effective in improving liver function and treatment of diseases of the liver and kidneys.