Background: Nephron-sparing surgery has been shown to achieve oncological results equivalent to those of radical nephrectomy in patients with compromised renal function who have renal tumors <4 cm. However, technical difficulties and potential surgical complications remain challenges to the surgeon. Various factors, such as tumor size and location, collecting system invasion, and patient's expectations, are major concerns that may affect the feasibility of performing an effective partial nephrectomy. We report a patient with renal cell carcinoma who underwent open partial nephrectomy and suffered from complications of perirenal abscess because of stone migration, obstruction, and subsequence urine leakage. Case Presentation: A 63-year-old female with an incidental finding of a 4-cm renal tumor on the left kidney underwent an effective open partial nephrectomy at our institute. There were no intraoperative complications and the drainage tube was removed 3 days later. The patient visited our emergency department 1 month later with high fever. She was diagnosed with severe sepsis and perirenal abscess formation. Percutaneous nephrostomy was performed for prompt decompression. A sequential imaging study with CT and antegrade pyelography revealed one 0.5-cm stone, which migrated from the calix to proximal ureter postoperatively and subsequently caused obstruction and dramatic urine leakage. Ureteroscopic lithotripsy was performed with ureteral stenting. Postoperatively, the urinary leakage and abscess formation resolved. Conclusion: Nephron-sparing surgery is one of the most challenging procedures in the management of renal cancer. Urine leakage after partial nephrectomy may occur when a large tumor involves the collecting system. Postoperative ureteral obstruction is also a risk factor of urinary leakage. Watertight repair with a Double J catheter before operation may be required.