We report a case of osteomyelitis of the pubis secondary to surgical site infection following colorectal cancer surgery. A 61-year-old male diagnosed with advanced upper rectum cancer and early descending colon cancer underwent laparoscopic low anterior resection and left hemicolectomy. However, four months after the initial surgery, a remnant cancer was observed. It was removed by super-low anterior resection. A median incision reaching the pubis was made without any exposure of the pubis. A surgical site infection, which developed after surgery, was drained; this led to the resolution of the infection. Four weeks after the second surgery, the patient developed bilateral groin pain and gait disturbance. Computed tomography revealed osteolysis of the pubis, indicating osteomyelitis. The patient was started on oral antibiotics; however, due to the progressive symptoms and computed tomography findings, the patient underwent debridement surgery. The patient was treated with intravenous antibiotics for 35 days and was discharged without any complications. Osteomyelitis of the pubis is a rare surgical complication and can lead to gait disturbance and chronic pain if treatment is delayed. Early diagnosis is critical in patients exhibiting symptoms suggesting osteomyelitis of the pubis after surgery for colorectal cancer surgery to avoid serious outcomes.