Background: Only comprehensive care and structured education can have a significant impact on the effectiveness of treatment and prepare patients for self-care. Unfortunately, Polish nurses are not ready to perform comprehensive heart failure (HF) care tasks without careful preparation.The purpose of the study was to evaluate nurses’ knowledge of patient education in general and topic-specific perceptions of basic information important for HF self-care, and also to determine the variables (workplace, education, internship) that may affect the implementation of educational tasks in the care of patients with HF. Methods: The study involved 304 nurses who were surveyed using the Nurses’ Knowledge of Heart Failure Education Principles. Results: Cardiology nurses’ knowledge regarding patient education for self-care is insufficient. The overall knowledge score was the highest among nurses in provincial specialist hospitals and university hospitals and the lowest in regional hospitals in small towns (14.98 vs. 14.35 vs. 12.83 vs. 11.89, respectively). Nurses who completed a cardiological specialty demonstrated significantly more extensive knowledge than those who had completed other specialties (15.52 vs. 13.71). Conclusions: Cardiology nurses’ knowledge of HF self-care principles regarding patient education is satisfactory, but not with all mandatory issues, especially in the recognition of disease symptoms, exacerbations, and pharmacotherapy.