Acute basilar artery occlusion (BAO) is a catastrophe with high mortality and disability. Randomized controlled trial (RCT) data supporting/refuting reperfusion treatment are sparse in acute BAO. The study objective was to pool risk estimates for death or dependency (DoD), mortality, and intracerebral hemorrhage (ICH) from published studies on BAO. Medline, Embase, The Cochrane Library, and clinicaltrials.gov were searched through August 2013 for studies of reperfusion therapies in acute BAO. Two independent authors selected studies and abstracted the data. Pooled risk ratios (RR) and mean weighted probabilities (MWP) were calculated using random effects model. 45 studies (n=2056) met the inclusion criteria. Recanalization was associated with a lower risk of DoD (RR 0.67; number needed to treat (NNT) 3) and mortality (RR 0.49; NNT 2.5). ICH rate (MWP) with acute therapies was 13%. With recanalization, RR for DoD in those treated ≤12 h was 0.63, and for those treated >12 h, it was 0.67. With recanalization, RR for DoD in the intravenous thrombolysis (IVT) subgroup was 0.68; in the intra-arterial/endovascular therapy (IA/EVT) subgroup, DoD RR was 0.67. Recanalization resulted in mortality RR of 0.46 in those treated ≤12 h; for >12 h group, RR was 0.50. Recanalization resulted in mortality RR of 0.53 in the IVT subgroup, and RR of 0.48 in the IA/EVT subgroup. ICH rate for ≤12 h was 10%; ICH rate for >12 h was 14%. With IVT, the ICH rate was 9%, and with IA/EVT the ICH rate was 14%. Recanalization of acute BAO leads to reduction in mortality by two-fold and reduction in the risk of DoD by 1.5-fold. This study underscores the equipoise in acute BAO for comparing systemic and endovascular therapies, and testing different time windows through RCTs.