Combined cognitive and physical exercise interventions have potential to elicit cognitive benefits in older adults with mild cognitive impairment (MCI) or dementia. This meta-analysis aims to quantify the overall effect of these interventions on global cognitive functioning in older adults with MCI or dementia. Ten randomized controlled trials that applied a combined cognitive-physical intervention with cognitive function as an outcome measure were included. For each study effect sizes were computed (i.e., post-intervention standardized mean difference (SMD) scores) and pooled, using a random-effects meta-analysis. The primary analysis showed a small-to-medium positive effect of combined cognitive-physical interventions on global cognitive function in older adults with MCI or dementia (SMD[95% confidence interval]=0.32[0.17;0.47], p<0.00). A combined intervention was equally beneficial in patients with dementia (SMD=0.36[0.12;0.60], p<0.00) and MCI (SMD=0.39[0.15;0.63], p<0.05). In addition, the analysis showed a moderate-to-large positive effect after combined cognitive-physical interventions for activities of daily living (ADL) (SMD=0.65[0.09;1.21], p<0.01)and a small-to-medium positive effect for mood (SMD=0.27[0.04;0.50], p<0.01). These functional benefits emphasize the clinical relevance of combined cognitive and physical training strategies.