We presented a case of a 63-year-old man with type 2 diabetes mellitus and end-stage renal disease on hemodialysis. Precontrast CT images showed atrophy of kidneys bilaterally and calcification of the abdominal aorta, small branches of bilateral renal arteries and small arteries of the pelvis, including the internal pudendal artery and penile artery. Postcontrast CT scans revealed a nonenhancing glans penis with a clear margin relative to normal tissue. The CT findings were compatible with gangrenous penis and were confirmed by surgery and histology. Findings of CT images can help urologists to decide the cutting margin in planning surgery.