Context:Transforming growth factor-beta 1 (TGF-beta 1), endothelin-1 and angiotensin II are responsible for extracellular matrix accumulation within the kidney in diabetic nephropathy. Objective:This study evaluated the effect of adding Gum Arabic (GA) and insulin on serum glucose, renal function, TGF-beta 1, endothelin-1, and angiotensin II in rats with diabetic nephropathy. Methods:Sixty male Sprague-Dawley rats were divided into; normal, normal plus GA, diabetic rats (DM), DM plus insulin, DM plus GA, and DM plus insulin plus GA groups. Levels of glucose and creatinine in serum, TGF-beta 1, angiotensin II, and endothelin-1 in renal homogenate and HbA1c were measured. Results:Serum creatinine, TGF-beta 1, angiotensin II, and endothelin-1 were increased in diabetic rats. GA decreased serum glucose, TGF-beta 1, angiotensin II, endothelin-1, and HbA1c in diabetic rats. GA and insulin decreased serum glucose, creatinine, TGF-beta 1, angiotensin II, endothelin-1, and HbA1c in diabetic rats. Conclusion:Co-administration of GA with insulin to rats with diabetic nephropathy improved the glycemic state, renal function, TGF-beta 1, endothelin-1, and angiotensin II.