Early reperfusion after endovascular thrombectomy is associated with an improved outcome in ischemic stroke patients; however, the time dependency in elderly patients remains unclear. We investigated the time-outcome relationships in different age subgroups. Of 2420 patients enrolled in the RESCUE-Japan Registry 2 study, a study based on a prospective registry of stroke patients with acute cerebral large-vessel occlusion at 46 centers, we analyzed the data of 1010 patients with successful reperfusion after endovascular therapy (mTICI of 2b or 3). In 3 age subgroups (< 70, 70 to < 80, and ≥ 80 years), the mRS scores at 90 days were analyzed according to 4 categories of onset-to-reperfusion time (< 180, 180 to < 240, 240 to < 300, and ≥ 300 min). In each age subgroup, the distributions of mRS scores were better with shorter onset-to-reperfusion times. The adjusted common odds ratios for better outcomes per 1-category delay in onset-to-reperfusion time were 0.66 (95% CI 0.55-0.80) in ages < 70 years, 0.66 (95% CI 0.56-0.79) in ages 70 to < 80 years, and 0.83 (95% CI 0.70-0.98) in ages ≥ 80 years. Early reperfusion was associated with better outcomes across all age subgroups. Achieving early successful reperfusion is important even in elderly patients.