A forty-year-old man developed right-sided neck discomfort whilst cycling to work. On admission to hospital he was found to have signs of bilateral cerebellar dysfunction. Magnetic resonance imaging of the brain demonstrated bilateral areas of cerebellar infarction. Doppler ultrasound of the vertebral arteries was abnormal and non-invasive gradient echo time of flight magnetic resonance angiography confirmed the clinical diagnosis of vertebral artery dissection. The patient was anticoagulated for a period of three months and made a full recovery.