This study analyzes data from a 2009 Commonwealth Fund survey of American physicians in internal medicine, family or general practice, or pediatrics to identify predictors of their having plans to retire or leave their practice for other reasons in the next 5 years. Just over half (53%) of physicians age 50 or older and 30% of physicians between age 35 and 49 have such plans. The strongest of the multiple predictors involved was time they spent coordinating care for patients. Factors that predict plans to retire differ from those associated with plans to leave practices for other reasons.