Purpose: The purpose of this systematic review was to identify exercise parameters and the most common outcome measures used in tai chi (TC) research. Methods: Ovid Medline and PubMed were used to identify longitudinal studies published from January 2000 to July 2007 written in English with the key words tai chi, tai ji, tai chi quan, tai ji quan, balance, falls, and falling. Qualifying studies had subjects aged 60 years or older. Results: In all 19 qualified prospective studies, older vigorous and likely transitional frail individuals seemed to benefit more from TC than did older frail individuals. The most commonly used TC parameters were Yang's style, with 12 or fewer forms, durations of 12 weeks or longer, frequencies of twice a week or more, and session lengths of at least 45 minutes. The most common outcome measures observed were a combination of 2 to 5 of the following 10 measures (from most to least common): fear of falling, single-leg stance, posturography, rate of falling, flexibility, walking velocity, Berg Balance Scale, Timed up and Go, Functional Reach, and ankle and knee joint strength and range of motion. Improvements were reported in almost all of these measures. Conclusions: This review indicates that TC may be an economic and effective exercise program for improving balance and balance confidence in older adults.