PURPOSE: To analyze and compare safety and efficacy of different endovascular treatment modalities for unruptured intracranial large or giant aneurysms. METHODS: We retrospectively reviewed 126 consecutive patients with 128 large (15-24 mm) or giant (>= 25 mm) aneurysms that were treated with different endovascular procedures between January 2014 and February 2017. We compared clinical and angiographic outcomes and occurrence of technical events among 3 treatment modalities. RESULTS: Complete occlusion at last follow-up was achieved in 65.6%, 90.5%, and 72.0% of aneurysms in stent-assisted coiling, parent artery occlusion, and Pipeline embolization device (PED) groups (P = 0.119). Complete occlusion rate at 6-month follow-up (odds ratio = 1.81, P = 0.396) and at last angiographic follow-up (odds ratio = 3.64, P = 0.123), was not superior with parent artery occlusion compared with PED. Retreatment rate was significantly different among all groups (P < 0.001); the rate was highest in the stent-assisted coiling group (21.9%). Rates of hemorrhagic events and ischemic events were not significantly different among groups (P = 0.581). Mass effect exacerbation was more frequently seen in the stent-assisted coiling group (24.4% vs. 7.7% and 3.3%, P = 0.004). Major complication rate was higher in the parent artery occlusion group compared with the PED group, but the difference was not statistically significant (19.2% vs. 16.4%, odds ratio = 1.21, P = 0.763). Rate of technical events was significantly different in the 3 groups (P = 0.0437), and technical events occurred more often in the PED group (18.0%). CONCLUSIONS: For large and giant aneurysms located in the internal carotid artery, outcome for endovascular treatment remains poor, even with the introduction of PED.