PURPOSE: We compared the characteristics and outcomes of patients treated with percutaneous nephrolithotomy in the CROES (Clinical Research Office of the Endourological Society) Global Study according to preoperative renal function. MATERIALS AND METHODS: Prospective data on consecutive patients treated with percutaneous nephrolithotomy in a 1-year period were collected from 96 participating centers. The glomerular filtration rate was estimated using the Modification of Diet in Renal Disease formula based on preoperative serum creatinine measurement. Patients were divided into 3 groups by glomerular filtration rate, including chronic kidney disease stages 0/I/II-greater than 60, stage III-30 to 59 and stages IV/V-less than 30 ml/minute/1.73 m(2). Patient characteristics, operative characteristics, outcomes and morbidity were assessed. RESULTS: Estimated glomerular filtration rate data were available on 5,644 patients, including 4,436 with chronic kidney disease stages 0/I/II, 994 with stage III and 214 with stages IV/V. A clinically significant minority of patients with nephrolithiasis presented with severe chronic kidney disease. A greater number of patients with stages IV/V previously underwent percutaneous nephrolithotomy, ureteroscopy or nephrostomy and had positive urine cultures than less severely affected patients, consistent with the higher incidence of staghorn stones in these patients. Patients with chronic kidney disease stages IV/V had statistically significantly worse postoperative outcomes than those in the other chronic kidney disease groups. CONCLUSIONS: Poor renal function negatively impacts the post-percutaneous nephrolithotomy outcome. By more aggressive removal of kidney stones, particularly staghorn stones, at first presentation and more vigilantly attempting to prevent recurrence through infection control, pharmacological or other interventions, the progression of chronic kidney disease due to nephrolithiasis may be mitigated.