Cement-augmented pedicle screws (CAPS) have been increasingly used in posterior fixation (PF) to enhance screw stability in patients with poor bone quality, particularly in metastatic spinal disease. Although adjacent vertebral fractures following cement-augmented fixation have been reported, vertebral fracture occurring within a vertebra instrumented with CAPS itself is rare. We report a case of delayed vertebral fracture in a CAPS-instrumented vertebra after PF for metastatic spinal disease. A 67-year-old woman with a history of breast cancer and pulmonary metastases presented with progressive back pain. She had previously undergone radiotherapy for metastasis at T10 vertebral body. Two years later, she developed a pathological fracture at T11 with dynamic kyphotic deformity. Imaging demonstrated osteolytic changes at the T10 level and collapse of the T11 vertebral body without spinal cord compression. Balloon kyphoplasty (BKP) at T11 combined with PF from T9 to L1 using CAPS was performed because compromised bone quality was anticipated to reduce fixation strength. Intraoperative biopsy showed no definite tumor cells. Postoperatively, local kyphosis improved and her symptoms were markedly relieved. Approximately three years after the first surgery, she developed recurrent severe back pain without trauma. Imaging revealed a new vertebral fracture at L1, which had been instrumented with CAPS, accompanied by back-out of the pedicle screw together with the cement mass. Serial computed tomography demonstrated progressive osteolytic changes at L1 prior to fracture, suggesting newly developed metastatic involvement. Revision surgery consisted of removal of the loosened screw, BKP at L1, and caudal extension of PF to L3 using CAPS. Her postoperative course was uneventful, and back pain improved markedly. This case highlights that vertebral fracture can occur within a CAPS-instrumented vertebra, particularly in the presence of progressive osteolytic disease. Careful long-term radiographic surveillance is important in patients with metastatic spinal disease treated with CAPS.