The management of subarachnoid haemorrhage by aneurysm rupture is well codified. Some rare cases can be problematical. We report a case of a patient suffering from factor VII (FVII) deficiency who presented a subarachnoid haemorrhage by sylvian aneurysm rupture. The bleeding risk was prevented by plasmatic factor VII substitution and aneurysm coiling. Anticoagulation in order to prevent from thromboembolic risk after embolisation was started for 36 hours, associated with plasmatic FVII substitution (with an objective of plasmatic FVII rate of 30%). After this stage at high thromboembolic risk, there has been no shift to platelet antiaggregants and FVII substitution was stopped. The outcome at 1 month was propitious without any bleeding nor arterial thrombosis.