We report the case of a 73-year-old man with an unruptured aneurysm of the left middle cerebral artery. The initial sign was complex partial seizures. A standard scalp electroencephalogram was normal while neuropsychological tests revealed a slight deficit of episodic memory. Brain MRI showed an aneurysm at the left middle cerebral artery bifurcation. Cerebral angiography confirmed the presence of a saccular aneurysm at the left middle cerebral artery bifurcation, with a maximum diameter of 12 mm. This case had two main characteristic features: seizures had a quite late onset and were the only symptom the patient experienced.