Purpose. The rectofemoral fistula represents a devastating complication of colorectal surgery. Its early diagnosis and treatment are critical to obtain a good patient outcome. Case Presentation. A 75-year-old Caucasian female patient presented with high fever, ileus, low back pain, sciatic nerve palsy, and infection of the right knee. After numerous surgical debridements and antibiotic therapies, a rectofemoral fistula was diagnosed. Conclusion. Increased doctors' alertness is mandatory for the early identification and surgical treatment of patients suffering from a rectofemoral fistula before the stage of diffuse infection has significantly decreases their postoperative morbidity and mortality.