Chronic kidney disease (CKD) is a worldwide public health problem, and proteinuria may accelerate the progression of CKD, being oxidative stress a common mechanism in nondiabetic or diabetic proteinuric kidney disease. This study was designed to evaluate the effect of the dietary supplementation with curcumin (CUR) on the redox status and the nuclear factor erythroid 2-related factor 2 (Nrf2) activation in patients with nondiabetic or diabetic proteinuric CKD.