Background: Asymptomatic intracerebral hemorrhage (AICH) is a common phenomenon in patients with acute ischemic stroke (AIS) who were treated with endovascular thrombectomy (ET). This study aimed to evaluate the clinical effects of AICH and its risk factors in this patient population. Methods: This observational study was based on a prospective registry study. AIS patients with large-vessel occlusion in the anterior circulation and treated with ET were recruited. During thrombectomy procedures, intra-arterial infusion of thrombolytics or antiplatelet and permanent stenting were used as remedial therapies. The primary outcome was the overall distribution of modified Rankin scale (mRS) 90days after ET. Results: This study included 102 patients (61.1 ± 12.7years old), in whom 39 patients (38.2%) experienced AICH. At 90-day follow-up, the median mRS was 2 (interquartile range [IQR] 0-3) for patients without AICH and 4 (IQR 2-6) for those with AICH (adjusted P =.005). Fourteen patients with AICH and 7 patients without AICH died, which was significantly different (35.9% versus 11.1%, adjusted P =.015). Thirty-nine patients (61.9%) without AICH and 14 patients (35.9%) with AICH achieved functional independence at 3-month follow-up (adjusted P =.117). The length of intensive care unit staying was 5days (IQR 2-10) in patients without AICH and 8days (IQR 3-19) in those with AICH (adjusted P =.840). In multivariate analysis, lower Alberta Stroke Program Early CT Score (ASPECTS) (adjusted P =.003) and adjunctively intra-arterial thrombolysis (adjusted P =.016) were independently associated with AICH. Conclusions: In AIS patients treated with ET AICH appears to be associated with worse functional outcomes and high mortality. Lower ASPECTS and adjectively intra-arterial thrombolysis were independent risk factors of AICH. ? 2019