To evaluate the impact of frailty on perioperative outcomes of older patients undergoing PCNL, utilizing the US Nationwide Inpatient Sample (NIS) database. Data of hospitalized patients >= 60 years who received PCNL were extracted from the 2010 to 2020 NIS database, and included demographics, clinical, and hospital-related information. Patients were assigned to low (< 5), medium (5-15), and high frailty risk (> 15) groups based on the hospital frailty risk score (HFRS). Associations between frailty risk and perioperative outcomes including total hospital cost were determined using population-weighted linear and logistic regression analyses. Data of 30,829 hospitalized patients were analyzed (mean age 72.5 years; 55% male; 78% white). Multivariable analyses revealed that compared to low frailty risk, increased frailty risk was significantly associated with elevated in-hospital mortality (adjusted odds ratio (aOR) = 10.70, 95% confidence interval (CI): 6.38-18.62), higher incidence of unfavorable discharge (aOR = 5.09, 95% CI: 4.43-5.86), prolonged hospital length of stay (LOS; aOR = 7.67, 95% CI: 6.38-9.22), increased transfusion risk (aOR = 8.05, 95% CI: 6.55-9.90), increased total hospital costs (adjusted Beta = 37.61, 95% CI: 36.39-38.83), and greater risk of complications (aOR = 8.52, 95% CI: 7.69-9.45). Frailty is a significant prognostic indicator of adverse perioperative outcomes in older patients undergoing PCNL, underscoring importance of recognizing and managing frailty in older patients.