Abstract Background and Purpose The benefit of endovascular thrombectomy (EVT) among nonagenarians (90 years or older) is poorly documented. We aimed to investigate the clinical and imaging factors associated with good outcomes and mortality at 90 days in nonagenarians undergoing EVT for acute ischemic stroke (AIS). Methods Data from a prospectively maintained institutional registry of consecutive AIS patients treated with EVT from January 2012 to December 2018 were retrospectively analysed. Comorbid conditions were classified with a modified version of the Charlson Comorbidity Index (CCI). The degree of disability was assessed by the modified Rankin Scale (mRS). Outcomes included good functional outcome (mRS scores of 0–3) and mortality at 90 days. Results Among 110 patients (age, 92.3 ± 2.5 years; men, 28.2%) treated with EVT, good outcome was achieved in 39 (35.5%) patients, successful reperfusion (modified Thrombolysis in Cerebral Infarction grades of 2b–3) was achieved in 78 (70.9%) patients and 38 (34.5%) patients died at 90 days. The functional outcome at 3 months was associated with pre-stroke status (CCI and pre-stroke mRS score). Successful reperfusion (adjusted odds ratio [OR], 11.6; 95% CI, 1.3–104.2; P = 0.03) and early neurologic improvement at 24 h (adjusted OR, 16.4; 95% CI, 5.2–51.5; P < 0.001) were independent predictors of a good outcome. Early neurological improvement (adjusted OR, 0.06; 95% CI, 0.02–0.23; P < 0.001) was an independent predictor of 90-day mortality. Conclusions Successful reperfusion therapy improves the functional outcome of nonagenarians who should not be excluded from EVT. The presence and severity of comorbidities should be considered in the procedural management of this vulnerable population.