Objective: To determine on the basis of a critical review and meta-analysis of the published literature whether physical exercises are beneficial for people with dementia and related cognitive disorders. Data Sources: A database of published and unpublished manuscripts from 1975 to October 2002 was compiled using MEDLINE, PubMed, CINAHL, AGELINE, Psyc-Lit, Educational Resources Information Center (ERIC), Sport Discuss (SIRC/CDC), Dissertation Abstracts, and a manual search. Key search words included physical activity, physical therapy, exercise, fitness, movement therapy, exercise rehabilitation, endurance, strength, aerobic training, flexibility, balance, aged, frail elderly, Alzheimer’s disease, dementia, cognitive impairment, and disability. Articles not written in English were excluded. Study Selection: To be included, reports had to meet the following criteria: (1) they had to evaluate the effects of intervention (exercise rehabilitation, program, or activities based on physical training), (2) they had to include older adults with cognitive impairments, (3) they had to evaluate outcome measures of physical fitness or health-related physical fitness components, cognitive and physical functioning, and behavior, (4) they had to include a control condition lacking exercise training, and (5) they had to use random assignment. Data Extraction: Two reviewers independently assessed the methodologic quality of the data of each included study. One reviewer extracted relevant meta-analysis data. Data Synthesis: Twenty-one randomized trials met the inclusion criteria and were analyzed. For each selected outcome, summary effects were computed by pooling standardized mean differences as well as raw mean differences. Significant improvements were found for all outcomes. The meta-analysis resulted in a significant homogenous standardized effect sizes with regard to strength (.78; 95% CI, .63–.93) and behavior (.67; 95% CI, .46–.87). The overall effect size (physical fitness, behavior, cognitive and functional performance), weighted by sample size, was d w equal to .67. This effect size index was converted to a U 3 value of .75, indicating that the average patient receiving a program of focused exercise rehabilitation performed better than approximately 75% of those patients in comparison groups. Conclusions: The results show promising evidence of the benefits of physical activity and exercise training on strength, behavior, functional performance, cognition, and physical health of older persons affected by dementia syndrome and related cognitive impairments.