Vertebral artery dissection used to be an uncommon diagnosis but it is now being diagnosed more frequently owing to the use of magnetic resonance imaging. We report on three patients with vertebral artery dissection to illustrate the importance of establishing this diagnosis by using magnetic resonance imaging in patients who present with cerebrovascular accident that involves the posterior territory. Treatment with heparin can help prevent recurrent embolic events and should be given in the absence of subarachnoid haemorrhage or other contra-indications.