Background and Purpose: Patients with prestroke mobility impairment (PSMI) were excluded from endovascular clinical trials. There are limited data regarding safety and outcomes of endovascular thrombectomy in this population. We used a large, national data set (Get With The Guidelines–Stroke) to evaluate the safety and outcomes of endovascular thrombectomy in patients with PSMI. Methods: We included patients who underwent endovascular thrombectomy in the Get With The Guidelines–Stroke registry between 2015 and 2019. PSMI was defined as the inability to ambulate independently. Generalized estimating equations for logistic regression models were used to evaluate the association between PSMI and outcomes. Results: Of 56 762 patients treated with endovascular thrombectomy, 2919 (5.14%) had PSMI. PSMI was not associated with symptomatic intracranial hemorrhage (6.0% versus 5.4%; P =0.979). In-hospital death or discharge to hospice occurred in 32.3% of patients with PSMI versus 17.5% without PSMI (adjusted odds ratio, 1.45 [1.32–1.58]). Conclusions: While procedural adverse outcomes were no higher in patients with PSMI, further study is necessary to determine clinical benefit in this population.