Acute basilar artery occlusion (BAO) is considered among the most severe medical emergencies, with very high morbidity and mortality. The aims of this study are to present 5 years experience of 12 centers in Lombardy region on BAO endovascular treatment and to evaluate prognostic factors that may improve clinical outcomes and recanalization rates.Registro Endovascolare Lombardo Occlusione Basilar Artery (RELOBA) registry is a retrospective multicentric collection of patients with acute BAO who underwent endovascular treatment between 2010 and 2015. A total of 102 patients (mean age 65 years) were included. Clinical, procedural, and neuroradiological data were collected. Angiographic results (Treatment in Cerebral Ischemia scale [TICI] score 2b-3) were assessed by each center's interventional neuroradiologist. Good clinical outcome was considered as a modified Rankin Scale score ranging between 0 and 2 in a 3-month follow-up.Thirty-nine percent of patients showed good clinical outcome at 3 months. Mortality rate was 30%. TICI 2b-3 was achieved in 62% of patients. Univariate analysis showed that age, National Institutes of Health Stroke Scale (NIHSS) at onset, time to recanalization, and TICI score were all statistically significant clinical outcome predictors (P.05). Multivariate logistic regression showed that time to recanalization, age, and NIHSS at onset were significant independent predictors of good outcome.BAO treatment needs more efforts to assure patients better clinical outcomes. Mechanical thrombectomy is feasible and effective in patients with acute BAO. These results must be confirmed by further prospective studies within randomized controlled settings.