Introduction: In this study it was aimed to evaluate the renal functions in Wilson’s disease (WD) using urinary N-acetyl-β-D-glucosaminidase (NAG) and NAG/ creatinine activity index. Materials and Methods: Twenty children of similar age and gender with WD were determined to be the patient group and 37 healthy children were determined to be the control group for the study. NAG levels were calculated as mlU/L and NAG activity index was determined as mlU/mg. Results: While four (20%) patients were asymptomatic at diagnosis, chronic hepatitis, neurologic WD, fulminant hepatitis, and acute hepatitis were observed in six (30%), five (25%), three (15%), and two (10%) patients, respectively. Of children, 13 (65%) were on trientine and zinc treatment and seven (35%) were on d-penicillamine and zinc. Ten (50%) children had proteinuria, one (5%) had glycosuria, and one (5%) had microscopic hematuria. While mean urine sodium and creatinine levels were significantly lower compared to controls (p=0.048 and p=0.001, respectively), NAG and NAG index were significantly higher (p=0.049 and p=0.03). Clinical presentation was observed to be not effective on those parameters (p>0.05). No relationship was found between Child-Pugh score and these parameters (p>0.05). Conclusions: It was concluded that while WD itself and/or the drugs that are used for the treatment have negative effects on renal functions for children with WD, however it does not have any effect on the liver damage severity and clinical presentation of the disease.