Background: The urachus is an embryological remnant of the urogenital sinus and allantois. Urachal carcinoma is a rare, aggressive malignancy with limited literature, often diagnosed late and associated with poor prognosis and high recurrence and metastatic potential. Case Presentation: We report a 58-year-old woman who presented with gross hematuria and lower urinary tract symptoms. Imaging showed a solid-cystic mass at the dome of the urinary bladder. Cystoscopic biopsy confirmed mucinous adenocarcinoma of urachal origin. She underwent tumor resection with partial cystectomy. After three years, she developed recurrence and was managed with re-resection and multiple cycles of chemotherapy, with suboptimal response. Conclusion: This case highlights the aggressive natural history of urachal adenocarcinoma, emphasizing the importance of early diagnosis, complete surgical resection, vigilant follow-up, and the limited efficacy of chemotherapy in recurrent disease.