Patients with heart failure (HF) frequently struggle to adhere to health behaviors, and psychological factors may contribute to nonadherence. We examined the feasibility and acceptability of a 10-week, positive psychology-(PP-) based intervention to promote health behavior adherence in patients (N=10) with mild to moderate HF and suboptimal health behavior adherence. Participants engaged in weekly phone sessions, completed PP exercises (e.g., writing a gratitude letter, using a personal strength), and set goals related to diet, medication adherence, and physical activity. Feasibility was assessed by the number of sessions completed, and acceptability by participant ratings of ease and utility. Preliminary efficacy was measured by changes in psychological and adherence outcomes. The intervention was feasible (87% of exercises completed) and acceptable. Furthermore, in exploratory analyses, the intervention was associated with improvements in psychological and health behavior adherence outcomes. Larger, randomized trials are needed to further investigate the utility of this intervention.