Background-Cardiac rehabilitation (CR) is recommended after coronary artery bypass graft surgery; however, the consequences of longer wait times to start CR have not been elucidated. Method and Results-Cardiopulmonary, demographic, and anthropometric assessments were conducted before and after 6 months of CR in consecutively enrolled patients from January 1995 to October 2012. Wait times were ascertained from referral forms and charts. Neighborhood characteristics were ascertained using census data and cross-referencing with patients' home geographic location. Among 6497 post-coronary artery bypass graft participants, mean and median total wait time (time from surgery to first exercise session) was 101.1±47.9 and 80 days, respectively. In multiple linear regression, correlates of longer total wait time and the 2 wait-time phases, time from surgery to CR referral and time from CR referral to first exercise session, were determined. Factors influencing longer wait times included female sex, greater age, being employed, less social support, longer drive time to CR, lower neighborhood socioeconomic status, higher systolic blood pressure, abdominal obesity, and a complex medical history. After adjusting for correlates of delayed entry, longer wait time for each of the total and 2 wait-time phases was significantly associated with less improvement in cardiopulmonary fitness (VO 2peak ; β=−0.165, P<0.001), body fat percentage (β=0.032, P<0.02), resting heart rate (β=0.066, P<0.001), and poorer attendance to CR classes (β=−0.081, P<0.001) and completion rate (β=2.741, P<0.001). Conclusions-Strategies for timely access to CR at each phase of the process are important given the negative impact that wait time has on key clinical outcomes. This is relevant because optimizing VO 2peak and attendance to CR has been shown to confer a mortality advantage. (Circ Cardiovasc Qual Outcomes. 2015;8:608-620.