Objectives: The main aim of this study was to compare the effects of different physical activities on cognitive functions in older adults divided according to cognitive impairment levels.Methods: We searched Web of Science, Scopus, and PubMed for randomized control trials (RCT). A standardized mean difference (SMD) of the pre-post intervention score of global cognitive function tests was calculated by the random model in the Cochrane meta-analyses for people with cognitive impairment generally and across three levels - borderline intact, mild, and moderate cognitive impairment separately. Additionally, an unstandardized coefficient beta (B) was calculated in generalized linear models to estimate the effects of exercise, cognitive impairment severity, age, female ratio, duration and frequency of exercise program on the global cognitive function.Results: Data from 40 studies involving 1,780 participants from intervention groups and 1,508 participants from control groups were analyzed. After sensitivity analysis, physical exercise had a positive effect on cognitive functions in people across all levels of cognitive impairments, SMD (95 % confidence interval [CI]) = 0.41 (0.29 - 1.54). All the activities were significantly associated with better results in global cognitive functions when compared to active control (B = 0.538 in aerobic, 0.999 in resistance, 0.640 in combined exercise and 0.746 in Tai Chi). Age was significantly associated with global cognitive functions decreasing and a higher number of female participants in intervention groups had a statistically significant effect on the global cognitive function (B = 0.021).Conclusions: Physical exercise was associated with cognitive function improvement in older people with cognitive impairments. Cognitive impairment severity was not associated with cognitive functions changes after exercise interventions.