Objective To examine the effect of a 12-week Tai Chi (TC) intervention on physical function and quality of life. Design Single-blind, randomized controlled trial. Setting General community. Participants Community-dwelling survivors of stroke (N=145; 47% women; mean age, 70y; time poststroke: 3y; ischemic stroke: 66%; hemiparesis: 73%) who were aged ≥50 years and were ≥3 months poststroke. Interventions Yang style 24-posture short-form TC (n=53), strength and range of movement exercises (SS) (n=44), or usual care (UC) (n=48) for 12 weeks. The TC and SS groups attended a 1-hour class 3 times per week, whereas the UC group had weekly phone calls. Main Outcome Measures Physical function: Short Physical Performance Battery, fall rates, and 2-minute step test; quality of life: Medical Outcomes Study 36-Item Short-Form Health Survey, Center for Epidemiologic Studies Depression Scale, and Pittsburgh Sleep Quality Index. Results During the intervention, TC participants had two thirds fewer falls (5 falls) than the SS (14 falls) and UC (15 falls) groups (χ2=5.6, P=.06). There was a significant group by time interaction for the 2-minute step test (F2,142=4.69, P<.01). Post hoc tests indicated that the TC (t 53=2.45, P=.02) and SS (t 44=4.63, P<.01) groups had significantly better aerobic endurance over time, though not in the UC group (t 48=1.58, P=.12). Intervention adherence rates were 85%. Conclusions TC and SS led to improved aerobic endurance, and both are suitable community-based programs that may aid in stroke recovery and community reintegration. Our data suggest that a 12-week TC intervention was more effective in reducing fall rates than SS or UC interventions. Future studies examining the effectiveness of TC as a fall prevention strategy for community-dwelling survivors of stroke are recommended.