SummaryDiabetic nephropathy, a microvascular complication of diabetes, is a progressive kidney disease caused by angiopathy of the capillaries in the kidney glomeruli. Herein, we report a case of a 62-year-old patient with a 30 year history of diabetes, who showed a substantial improvement in diabetic nephropathy on administration of 30 g of Astragalus membranaceus extract per day. After 1 month, estimated glomerular filtration rate increased from 47 to 72 ml/min per 1.73 m² and was subsequently maintained at the 1-month follow-up. Urinary protein levels also decreased following treatment. Herein, we present and discuss the evidence and mechanism of A. membranaceus on diabetic nephropathy in this patient.Learning pointsDiabetic nephropathy is a progressive kidney disease.Angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) are currently used to prevent and delay the progression of diabetic nephropathy. However, their effects are not sufficient to prevent a decline in kidney function.Furthermore, combination therapy with an ACE inhibitor and an ARB can produce adverse effects without additional benefits.In the early phase of diabetic nephropathy, administration of Astragalus membranaceus can be a therapeutic option.