The frequency of stroke mimics among stroke patients has been reported to be up to 30%, and that in patients who receive thrombolytic therapy ranges between 1% and 16%. Atlantoaxial dislocation with myelopathy mimicking stroke is extremely rare. An 83-year-old man with a history of old cerebellar infarction presented to the emergency department with acute left hemiplegia after a chiropractic manipulation of the neck and back several hours before symptom onset. Mild hypoesthesia was observed on his left limbs. No speech disturbance, facial palsy, or neck or shoulder pain was observed. Intravenous thrombolytic treatment was given 238 min after symptom onset. Brown–Sequard syndrome subsequently developed 6 h after thrombolysis with a hypoesthetic sensory level below the right C5 dermatome. An emergent brain magnetic resonance angiography did not reveal an acute cerebral infarct but rather an atlantoaxial dislocation causing upper cervical spinal cord compression. Clinical symptoms did not deteriorate after thrombolysis. He received successful decompressive surgery 1 week later, and his muscle power gradually improved, with partial dependency when performing daily living activities 2 months later. A literature review revealed that only 15 patients (including the patient mentioned here) with spinal disorder mimicking acute stroke who received thrombolytic therapy have been reported. Atlantoaxial dislocation may present as acute hemiplegia mimicking acute stroke, followed by Brown–Sequard syndrome. Inadvertent thrombolytic therapy is likely not harmful for patients with atlantoaxial dislocation-induced cervical myelopathy. The neurological deficits of patients should be carefully and continuously evaluated to differentiate between stroke and myelopathy.