[Objective] It has been reported that everyday physical activity, exercise, and physical fitness in older adults affect their cognitive function. However, to our knowledge, no empirical evidence of this effect has yet been reported in convalescent patients with cognitive impairment after cerebrovascular disease. Therefore, it is important to clarify this point for patients with cerebrovascular disease, in order to efficiently improve their cognitive impairment during rehabilitation. The aim of this study was to estimate the amount of total energy expenditure during hospitalization, and to investigate the association between total energy expenditure and cognitive function in patients convalescing after cerebrovascular events. [Methods] We recruited 24 patients (16 men and 8 women; mean age 68.8±10.6 years) with cerebrovascular disorders. The total energy expenditure per day was estimated for each subject by the factorial method for 5 months. Cognitive function was assessed using items of the Functional Independence Measure (FIM). [Results] Both total energy expenditure and cognitive items on the FIM increased significantly (p<0.001) during the 5 months. A significant correlation was found between them (r=0.294, p=0.001), and also a significant partial correlation between them (r=0.221, p=0.016) in determining weight as a control variable. Moreover, there was a significant partial correlation between gain in total energy expenditure and gain in the cognitive items of the FIM in determining the baseline scores of cognitive function as a control variable (3 months: r=0.466, p=0.044; 5 months: r=0.485, p=0.035). [Discussion] We conclude that there is a relationship between total energy expenditure and cognitive function in patients convalescing after cerebrovascular events.