Abstract: Urachal abscess, caused by congenital developmental anomalies of the urachus, is clinically rare and may present with abdominal pain, a palpable mass in the middle of the lower abdomen, and fever, making it easily to misdiagnosis as urachal carcinoma. The authors report a case of a 25-year-old male patient with urachal abscess who presented primarily with abdominal pain and fever, and summarize the characteristics of the disease based on clinical manifestations, laboratory tests, and whole-body ¹⁸F-FDG PET/CT imaging findings, with the aim of improving clinicians' and radiologists' understanding of this disease and diagnostic accuracy.