Provided is a renal function improving agent that is usable for preventing or suppressing a worsening in renal function without largely changing previous eating habits. A renal function improving agent to be taken by a person who shows an abnormal value of at least one factor selected from blood urea nitrogen concentration, blood creatinine concentration and daily urinary albumin excretion, said renal function improving agent comprising, per 100 kcal of energy, 0.5-4 g of protein, 10-40 mg of phosphorus, 10-70 mg of sodium and 5-50 mg of potassium.本發明提供一種腎機能改善劑，其係不會大幅改變目前的飲食習慣，並且可使用於防止或抑制腎機能的惡化等。一種腎機能改善劑，其係讓血中尿素氮濃度、血中肌酸酐濃度、尿中白蛋白每天的排泄量之中的一種以上出現異常值者攝取之腎機能改善劑，並且每100kcal的能量中，蛋白質含量為0.5~4g、磷含量為10~40mg、鈉含量為10~70mg、鉀含量為5~50mg。
