RATIONALE:: This report presents a case of an elderly male patient with adult spinal deformity and an atlas fracture without trauma that was assessed by the global parameter of spinal alignment using free-standing radiography and discusses its etiology with a literature review. PATIENT CONCERNS:: An 84-year-old man presented with severe neck pain, but no history of trauma. Neck pain worsened when he gazed forward. DIAGNOSIS:: Freestanding radiography showed degenerative lumbar kyphoscoliosis (L1-5 Cobb: 19º, lumbar lordosis: 9º), and spinopelvic harmony was significantly disturbed to a pelvic tilt of 43º and PI-LL of 50º. He managed to maintain trunk balance in the sagittal vertical axis (86.6 mm) by extending his hip and decreasing his thoracic kyphosis to 7º. However, the cervical spine has degenerative, ridged, and kyphotic deformity. Owing to this deformity and the insufficient compensatory mechanism from the thoracic spine to the lower extremity for degenerative lumbar kyphoscoliosis, the occipitoaxial angle was largely increased to 43º to achieve horizontal gaze, and the posterior arch of the atlas was in contact with the occipital and spinous processes of C2. Computed tomography showed fractures of the anterior and posterior arches of the atlas, and T2-weighted magnetic resonance imaging showed a low-intensity area around the fracture line, which is frequently observed in late stress fractures. This atlas fracture was eventually diagnosed as a stress fracture resulting from repetitive collisions with the occipital and spinous processes of C2 caused by the global spinal compensatory mechanism for sagittal imbalance. INTERVENTIONS:: Osteosynthesis using C1 lateral mass screws and rod was performed for this stress fracture of atlas. OUTCOMES:: His neck pain dramatically reduced postoperatively, and he could get the frontal gaze more easily than before the surgery. LESSONS:: This report illustrates a rare case of stress fracture of the atlas in an elderly patient, and highlights the importance of assessing global balance.