Here we present the first reported case of three-dimensional CT-guided salvage brachytherapy of recurring colorectal cancer in the pelvis after failed radiation therapy, total colectomy, and chemotherapy. Initial CEA was 67.0 ng/mL and tumor volume 93 cm3 with no metastasis outside the pelvis. A total of 333 seeds of Iodine-125 were delivered to the entire target, with dosage of 150 to 200 Gy as calculated by post-implant CT dosimetry with Varian MMS software. CEA 12 months after implant decreased to 5.7 ng/mL. Clinical and biochemical results are encouraging; however long-term data in a greater universe of patients are required.