Objective: To report a case with sudden-onset tetraparesis during taking magnetic resonance imaging (MRI).Case report: A 73-year-old man was referred with complaints of paresis of his arms and legs. His tetraparesis had developed suddenly while an MRI was performed 10 days before. He had a severe tetraparesis with 0/5 motor strength in his legs and 2/5 motor strength in his arms. On the MRI, a serious spinal stenosis at C3-4 and C4-5 levels and a faint myleopathic signal of the spinal cord at the level of the C4-5 disc space were seen. After posterior decompression, the patient’s tetraparesis improved gradually and he could walk independently and perform his daily activities with mild spasticity after 13 months.Conclusion: It is known that sudden neurological deficits may be seen in cervical trauma in patients with cervical spinal stenosis due to spondylosis. However, this case who did not have a trauma history showed us that a long period of positioning the neck beyond the patient’s control, even during the execution of MRI, may cause sudden deterioration.