Objective: The purpose of this research was to investigate the real-world effectiveness of speech therapy time on cognitive recovery in older patients with acute stroke. Methods: The participants of this retrospective cohort study were hospitalized patients with acute stroke registered in the Japan Rehabilitation Database between December 2005 and September 2014. The patients were divided into two groups according to the amount of time they spent undergoing speech therapy, i.e., a high-intensity speech therapy group and a control group. Multivariate linear regression analysis was performed to assess the association between cognitive Functional Independence Measure efficiency and high-intensity speech therapy. Results: Of the 3341 eligible stroke patients (mean age: 77 years) extracted from the database, 53% received high-intensity speech therapy. Patients in the high-intensity speech therapy group had significantly higher cognitive Functional Independence Measure efficiency scores than those in the control group (mean, 0.17 vs. 0.10, respectively; P < 0.001). Multivariate regression analysis showed that cognitive Functional Independence Measure efficiency was significantly and positively correlated with high-intensity speech therapy (coefficient, 0.03; 95% confidence interval, 0.004-0.056; P = 0.026). Conclusions: These data suggest that a large amount of speech therapy time in older patients with acute stroke is a significant predictor of good cognitive recovery. Increased amounts of speech therapy for such patients may lead to better cognitive recovery after stroke.