<p>Early implementation of advance care planning (ACP) is recommended in heart failure (HF) in accordance with patients’ preferences. However, preferences regarding ACP among patients with acute coronary syndrome (ACS)—a spectrum encompassing precursor and symptomatic HF—remain unclear. We aimed to clarify patients’ preferences regarding ACP and actual engagement in ACP and prognostic communication with physicians in ACS and identify factors associated with ACP preferences. This cross-sectional, questionnaire-based study enrolled patients with ACS who underwent cardiac rehabilitation at a university-based hospital. The questionnaire assessed preferences for ACP and information disclosure by physicians, HF understanding, and depressive symptoms. Univariable logistic regression analyses were performed to identify factors associated with positive preferences for ACP. Overall, 277 patients (median age: 69&#xa0;years; men: 80.5%; 78.3% with precursor HF and 21.7% with symptomatic HF) were enrolled. Of them, 77.3% expressed a preference for ACP conversations, whereas only 27.1% participated in them. Regarding prognostic communication, 59.9% desired more information; 25.5% reported that such discussions occurred less frequently than preferred. Positive preferences for ACP were associated with lower depression symptoms, better understanding of HF’s impact on life expectancy, higher frequency of prognostic communication, and a desire for more prognostic information but not with the presence of symptomatic HF or age. Most patients with ACS expressed positive preferences for ACP conversations and prognostic communication; however, a substantial gap persists between preferences and practice. Strategies to promote ACP implementation among patients with positive preferences, irrespective of age or HF stage, are warranted.</p>