Background Social support can influence treatment adherence of patients with chronic illnesses, which may explain the positive effects of social support on heart failure (HF) outcomes. Purpose To investigate the effects of social support among patients with HF, we examined whether aspects of social support were associated with self-care, including medication adherence, dietary adherence, and HF symptom monitoring functions. Methods We recruited 74 patients with HF from cardiology clinics of a Veterans Affairs Medical Center and a university-affiliated hospital, and tested the relationships between social support and the patients' self-care. Results Consistent with previous research in older adults, family members, especially spouses, were often involved in the medical care of patients with chronic HF and provided a range of levels of support to patients. Self-care was generally poor, as measured across several self-care domains. Perceived social support was moderately associated with relatively better self-reported medication and dietary adherence, and other aspects of self-care such as daily weighing. Conclusions These findings suggest that a relatively higher level of self-care is an important correlate of social support and may explain how social support influences HF outcomes. This study also suggests that family members should play a greater part in clinical care focused on improving self-care.