The natural history of giant intracranial aneurysms are grave. More than 50% of patients suffer from rupture of these aneurysms and mortality is >60% in 2 years. Modern technology and advancement of knowledge in neurosurgery and interventional neuroradiology have altered its natural course for the better. As many reports have shown, the majority of these aneurysms can be treated either by surgery or by endovascular approach, even though morbidity is higher than when treating smaller aneurysms. Certain aneurysms are more suitable to direct surgical clipping and others may have better chances of good clinical outcome by endovascular treatment. It is imperative to analyse the location, morphology, hemodynamics and circulation of normal brain of each aneurysm before the mode of treatment is decided. Needless to say, the individual patient's age, neurological and medical condition should be considered. For endovascular treatment, application of each technique, endosaccular occlusion or parent artery occlusion depends on the aneurysm location and geometry as well as its pathology. Several reports indicated that clinical outcome is better in patients treated by parent artery occlusion since it eliminates any blood flow to the aneurysm and it provides a more effective reduction of the mass effect. However, not all parent arteries can be sacrificed. In addition, endosaccular treatment is effective in preventing haemorrhage if the aneurysm is not re-canalised. It is also demonstrated that symptoms of mass effect can be reversed by endosaccular coiling. The patients who are treated this way should be closely monitored for re-canalisation.