Background <p>Penile calciphylaxis is a rare condition with a poor prognosis. Although the median time to onset in patients undergoing dialysis is approximately 48 months, reports of early onset shortly after dialysis initiation are rare.</p> Case presentation <p>A 50-year-old man with diabetic nephropathy underwent an ABO-incompatible living donor kidney transplantation from his father and continued immunosuppressive therapy with steroids and calcineurin inhibitors. Despite transplantation, glycemic control remained poor, and renal function gradually deteriorated. Maintenance dialysis was initiated 6 years and 8 months after transplantation. Immunosuppressive therapy, including steroids, was tapered but continued after dialysis initiation. Eight months later, the patient developed pain and discoloration at the tip of the penis and was hospitalized with suspected calciphylaxis. Imaging revealed severe calcification of the dorsal and deep penile arteries. Although conservative treatment was initially considered, the patient developed delirium due to persistent severe pain and experienced multiple falls, resulting in a right femoral trochanteric fracture. Considering the limitations of conservative management, surgical resection of the necrotic penile tissue was performed. Postoperatively, his pain improved, and there was no further progression of necrosis, allowing transfer to a rehabilitation facility. Histopathological examination using Von Kossa staining confirmed the diagnosis of calciphylaxis.</p> Conclusions <p>This case suggests that calciphylaxis can develop shortly after dialysis initiation if multiple risk factors are present. Awareness that calciphylaxis can affect the penis is important, and early detection and treatment may be facilitated by close monitoring of penile arterial calcification in patients with multiple risk factors.</p>