Purpose: The management of tandem extracranial internal carotid artery and intracranial large vessel occlusion during endovascular thrombectomy (EVT) for acute ischemic stroke (AIS) has been under-investigated. We sought to investigate outcomes of AIS patients with tandem occlusion (TO) treated with carotid artery stenting (CAS) compared to those not treated with CAS (no-CAS) during EVT. Methods: We performed a cohort study using data from AIS patients enrolled in the Italian Registry of Endovascular Treatment in Acute Stroke. Outcomes were 3 months’ mortality, functional outcome, complete and successful recanalization, any intracranial hemorrhage, parenchymal hematoma and symptomatic intracerebral hemorrhage. Results: Among 466 AIS patients with TO, CAS patients were 122 and no-CAS patients were 226 (118 excluded). After adjustment for unbalanced variables, CAS was associated with a lower rate of 3 months’ mortality (OR 0.407, 95% CI 0.171–0.969, p= 0.042). After adjustment for pre-defined variables, CAS was associated with a lower rate of 3 months’ mortality (aOR 0.430, 95% CI 0.187–0.989, p= 0.047) and a higher rate of complete recanalization (aOR 1.986, 95% CI 1.121–3.518, p= 0.019), successful recanalization (aOR 2.433, 95% CI 1.263–4.686, p= 0.008) and parenchymal hematoma (aOR 2.876, 95% CI 1.173–7.050, p= 0.021). CAS was associated with lower 3 months mortality (OR 0.373, 95% CI 0.141–0.982, p= 0.046) and higher rates of successful recanalization (OR 2.082, 95% CI 1.099–3.942, p= 0.024) after adjustment for variables associated with 3 months’ mortality and successful recanalization, respectively. Conclusions: Among AIS patients with TO, CAS during EVT was associated with a higher rate of successful reperfusion and a lower rate of 3 months’ mortality.