Purpose: This study explored patients’ decision-making about whether or not to enroll in cardiac rehabilitation (CR), an underutilized program that is associated with significantly improved health outcomes. Method: Face-to-face interviews were conducted with acute coronary syndrome patients (n = 14) after referral to a local CR center, but prior to program enrollment. Thematic analysis was used to derive themes from interview transcripts. Results: Three themes emerged including anticipated benefit, perceived ability, and contextual influences. Participants believed key benefits of CR would be access to specialist healthcare providers, improved longevity, reduced cardiovascular risk, as well as improved motivation, accountability, learning opportunities, and general fitness. Participants were concerned about their ability to engage in and travel to exercise sessions, pay the program fee, and manage scheduling conflicts. Contextual influences on decision-making included healthcare provider recommendation, first impressions of the CR center, knowledge gaps about what CR entails, input from family and peers, and psychological distress. Conclusion: The period following CR referral but prior to enrollment represents an optimal opportunity to promote in-the-moment decisions in favor of CR. Patients report both positive and negative aspects of CR, suggesting individualized efforts to resolve ambivalence may increase program participation.