Heart failure, a common syndrome in developed countries worldwide, is associated with poor quality of life, frequent rehospitalizations, and early death. Self-care is essential to improving outcomes in this patient population. The purpose of this article is to describe a situation-specific theory of heart failure self-care in which self-care is defined as a naturalistic decision-making process involving the choice of behaviors that maintain physiologic stability (maintenance) and the response to symptoms when they occur (management). Self-care maintenance is further defined to encompass routine symptom monitoring and treatment adherence. Self-care management is characterized as a process initiated by symptom recognition and evaluation, which stimulates the use of self-care treatments and treatment evaluation. Confidence in self-care is thought to moderate and/or mediate the effect of self-care on various outcomes. Four propositions were derived from the self-care of heart failure conceptual model: (1) symptom recognition is the key to successful self-care management; (2) self-care is better in patients with more knowledge, skill, experience, and compatible values; (3) confidence moderates the relationship between self-care and outcomes; and (4) confidence mediates the relationship between self-care and outcomes. These propositions were tested and supported using data obtained in previous research. Support of these propositions provides early evidence for this situation-specific theory of heart failure self-care.