Ectopic ureter refers to a congenital anomaly in which one or both ureters do not connect to the urinary bladder at the correct anatomical site. This case report discusses the case of a 6-year-old female mixed-breed dog diagnosed with chronic urinary incontinence, systemic hypertension, pancreatitis, and sepsis resulting from an ectopic ureter. Treatment involved an initial nephro-ureterectomy to address severe pyonephrosis, followed by ureteroneocystostomy for the remaining functional kidney. Post-surgical outcomes showed notable improvements in clinical symptoms, laboratory findings, and blood pressure. This report emphasizes the need for early diagnosis and appropriate surgical treatment in cases of ectopic ureter. Additionally, it aims to present the clinical symptoms and conditions resulting from prolonged disease progression, as well as the corresponding treatment methods and prognosis.