OBJECTIVES: To assess the impact and availability of ureteroscopy-assisted puncture for percutaneous renal access during ultrasonography-guided miniaturized (mini)-endoscopic combined intrarenal surgery for large volume renal and/or proximal ureteral stones. METHODS: We conducted a multi-institutional retrospective cohort study for urolithiasis treatment. Data from a total of 313 patients who underwent mini-endoscopic combined intrarenal surgery to treat renal and/or ureteral stones between January 2016 and April 2020 were collected. We compared the outcomes between ultrasonography-guided mini-endoscopic combined intrarenal surgery with and without ureteroscopy-assisted puncture (ureteroscopy-assisted puncture(+) group [n = 126] and ureteroscopy-assisted puncture(-) group [n = 187] group, respectively). The primary outcome was requirement for additional surgical intervention. Secondary outcomes were stone-free rate, complications and total procedure, fluoroscopy, hospital stay, and postoperative ureteral stent placement durations. RESULTS: The ureteroscopy-assisted puncture(+) group had a lower additional surgical intervention rate and a higher stone-free rate immediately after and 3 months after surgery than the ureteroscopy-assisted puncture(-) group (5.6% vs 19.7%, P < 0.001; 82.5% vs 65.8%, P = 0.001; 59.5% vs 44.6%, P = 0.011). The median total procedure, fluoroscopy, and postoperative ureteral stent placement durations were 18 min, 3 min, and 5 days shorter, respectively, in the ureteroscopy-assisted puncture(+) group. Multivariate analyses showed that ureteroscopy-assisted puncture was associated with a decreased risk of additional surgical intervention (odds ratio 0.31, P = 0.011) and postoperative infection (odds ratio 0.34, P = 0.003) and decreased total procedure (estimate = -11 min; P = 0.011), fluoroscopy (estimate = -3 min; P = 0.034), and postoperative ureteral stent placement (estimate = -8 days; P = 0.011) durations. Female patients and those with smaller stone volumes or without hydronephrosis were identified as ideal ureteroscopy-assisted puncture candidates. CONCLUSIONS: Ureteroscopy-assisted puncture during mini-endoscopic combined intrarenal surgery could provide favorable surgical outcomes, especially in female patients without collecting system obstruction.