Coconut water (CW) is a natural nutritious beverage, which contains several biologically active compounds that are traditionally used in the treatment of diarrhea and rehydration. Several works with CW have been related with antioxidant activity, which is very important in the diabetic state. To evaluate the hypoglycemic and nephroprotective activities of CW, alloxan-induced diabetic rats were pre- and post-treated by gavage with CW (3 mL/kg), caffeic acid (CA) (10 and 15 mg/kg), and acarbose (Acb) (714 μg/kg) during a period of 16 days. Body weight, blood glucose, glycated hemoglobin (HbA1c), and Amadori products in plasma and kidney homogenates were evaluated in all groups and used as parameters for the monitoring of the diabetic state. The results showed that rats of the CW+diabetic group had maintenance in blood glucose compared with the control group (P<.05) in addition to a decrease of HbA1c levels and increase of body weight when compared with the diabetic group rats (P<.05). The animals of the CA and CA+diabetic groups did not have significant variation of body weight (P<.05) during the experiment; however, they showed decrease in their HbA1c and urea levels in plasma as well as Amadori products in kidney homogenates when compared with the diabetic group (P<.05). Our results indicate that CW has multiple beneficial effects in diabetic rats for preventing hyperglycemia and oxidative stress caused by alloxan.