Since percutaneous nephrolithotomy (PNL) is a surgical intervention, it may show deteriorative effects on renal function in the early postoperative period. In this study, the deteriorative effects of PNL on renal function were investigated in the geriatric population, and it was compared to the non-geriatric population.A total of 711 patients [64 in the geriatric group (female/male ratio: 33/31, mean age: 70.4 +/- 4.2 years), 647 in the non-geriatric group (female/male ratio: 267/380, mean age: 40.9 +/- 12.7 years)] were included in the study. Demographic data, biochemical parameters, stone diameters, duration of the operation and estimated glomerular filtration rates (eGFR) were recorded both preoperatively and postoperatively.The eGFR ratio (post-/preoperative) was 1.13 +/- 1.00 in the geriatric group, 0.98 +/- 0.20 in the non-geriatric group (P < 0.001). Although the mean stone diameter was larger in the geriatric group than the non-geriatric group (10.08 +/- 6.5 mm, 8.28 +/- 5.54 mm, P = 0.037), the mean duration of the operation was shorter in the geriatric group than in the non-geriatric group (55.7 +/- 13.6 min, 61.3 +/- 20.9 min, P = 0.036). Hematocrit, hemoglobin, urea levels, and grade of hydronephrosis were not different between the groups.Renal function impairment is expected to be common in the geriatric patient population since they already have lower basal renal function. In the present study, the ratio of postoperative to preoperative eGFR was higher in the geriatric group. Hematocrit, hemoglobin, and urea levels and degree of hydronephrosis of these two groups did not show a great difference. The relatively short duration of the operation in the geriatric group and the diversity of perioperative and postoperative care of these two groups may explain the difference.