Objective: To retrospectively evaluate the safety and efficacy of flexible ureteroscopy (FURS) in combination with holmium laser lithotripsy for the treatment of bilateral upper urinary calculi. Materials and Methods: The stone-free status was defined as the absence of any stones or asymptomatic status, or the presence of clinically insignificant residual fragments <4 mm, and was assessed by plain kidney, ureter, and bladder X-ray. The operative time, stone-free rates (SFRs), serum creatinine (SCr), and complications were recorded. Results: During the operation, there was no bleeding, ureteral perforation, avulsion, and rupture. Postoperative hematuria was observed in 2 patients. SCr increased significantly on the first day after the procedure compared with the preoperative SCr, but after 4 weeks, the renal function significantly improved (p < 0.05). The SFR was 71.6% (63/88) on the first day after the first surgical procedure; it then increased to 86.4% (76/88) in the fourth week, and rose to 97.4% (76/78) after the second operation. Conclusion: The results demonstrated that FURS in combination with holmium laser lithotripsy represented a favorable less-invasive alternative with high SFR and acceptable complication rates in the treatment of bilateral upper urinary tract calculi.