AIM: We aimed to examine the association between physical activity (PA) and/or cognitive activity (CA) and cognitive impairment in a sample of older adults from a community-based cohort in Nagoya, Japan. METHODS: A total of 2726 participants (mean age 75.5 ± 3.9 years; 51.8% women) met the study criteria. The time of moderate-to-vigorous intensity PA was measured using an accelerometer. CA was subjectively assessed by the frequency of engagement in six activities (reading, writing for pleasure, doing crossword puzzles, playing board games/cards, participating in organized group discussions and playing musical instruments). Participants were categorized into four groups by high or low PA combined with high or low CA. Cognitive impairment was defined by at least one of four neuropsychological tests with a result of at least 1.5 standard deviations below the reference threshold. RESULTS: The prevalence of cognitive impairments differed significantly between the groups (P < 0.001), with 29.5% in the low PA and low CA group, to 14.8% in the high PA and high CA group. Compared with the low PA and low CA group, other groups had significantly lower odds ratio (OR) of cognitive impairment (low PA and high CA: OR 0.54, 95% CI 0.37-0.79; high PA and low CA: OR 0.64, 95% CI 0.45-0.92; high PA and high CA: OR 0.42, 95% CI 0.30-0.58). CONCLUSIONS: Both PA and CA showed a protective association with cognitive impairment, even when one or the other is lowly engaged. Therefore, older adults with difficulty engaging in sufficient PA might benefit from CA to prevent cognitive impairment. Geriatr Gerontol Int 2020; 20: 31-35.