A 4-year-old Yorkshire Terrier presented to Cornell University Hospital for Animals’ (CUHA) Neurology Service for atlantoaxial instability. His clinical signs included neck pain, ataxia, and rolling, circling, and turning to the right. On presentation, his neurologic exam revealed a mild right head turn, a body angled slightly to the right, an ambulatory left-lateralizing hemiparesis with intermittent knuckling on the left thoracic limb, decreased proprioceptive placing on the left thoracic and pelvic limbs, and pain on palpation of the cranium and cervical vertebrae. He was neurolocalized to a C1-C5 myelopathy. Imaging confirmed atlantoaxial instability with spinal cord compression. Ventral stabilization surgery was performed. During his 11 day in-hospital post-operative recovery his neurologic examination improved to a mildly delayed proprioceptive placing and hopping on the left thoracic and pelvic limbs. Stabilization also improved his gait to a very mild left-sided hemiparesis without any knuckling and he was able to turn his head in both directions. This case report will describe the treatment options for atlantoaxial instability and their possible complications.