Recent studies have demonstrated more than 30% of percutaneous nephrolithotomy (PCNL) patients will experience a stone recurrence over a 20 year period. The goal of our study was to identify risk factors for stone recurrence after PCNL. Chart review identified 754 patients treated with PCNL for urolithiasis from March of 1983 to July 1984 at our institution. Of this cohort, 87 patients continued to receive medical care at our clinic and had been evaluated within the last 5 years. Of the 87 patients, 80 had recent radiographic imaging. Average follow-up was 19.2 years and 32 (40.0%) experienced at least 1 stone recurrence. There was no difference in preoperative BMI (p=0.453) or change in BMI (p=0.964) between patients that did and did not have a stone recurrence. Renal stone location (p=0.605) and stone size (p=0.238) were not predictive of recurrence. Patients with calcium oxalate monohydrate stones were less likely to recur (38.7% vs. 41.6%, p=0.004) and those with calcium oxalate dihydrate (COD) were more likely to recur (31.1% vs. 19.6%, p=0.006) compared to other compositions. Diabetes mellitus was not associated with recurrent stones (p=0.810). Those patients with residual stones or fragments <3 mm were more likely to recur and to recur earlier than patients rendered entirely stone free at time of PCNL (p=0.015). Stone recurrences were associated with the late development of renal insufficiency (25% vs. 2.1%, p=0.002). In conclusion, stone composition, as well as the presence of residual fragments was associated with recurrent symptomatic stone events after PCNL. Recurrent stone events were significantly associated with the risk of developing renal insufficiency, further stressing the need for complete stone clearance at time of PCNL.