Background: One of the primary reasons for hospitalisation among elderly individuals with heart failure (HF) is poor self-care. Self-awareness of having HF may be a key-element in successful self-care. The prevalence of self-awareness of HF, and how it is affected by age-and HF-related factors, remains poorly understood. The aims of the present study were to determine the prevalence of self-awareness of HF in participants, ≥ 80 years of age, and to investigate the association between this self-awareness and age-related and HF-related factors. Methods: A single-centre observational study was conducted in which non-hospitalised participants (80+) with objectively verified HF were identified (n = 90). The statement of having HF or not having HF was used to divide the participants into two groups for comparisons: aware or unaware of one’s own HF. Logistic regression models were completed to determine the impact of age-and HF-related factors on self-awareness. Results: Twenty-six percent (23/90) were aware of their own HF diagnosis. No significant differences were found between the participants who were aware of their own HF diagnosis and the participants who were not. Neither age-nor HF-related factors had influence on the prevalence of self-awareness. Conclusions: Prevalence of self-awareness of own HF in the oldest old is insufficient, and this self-awareness may be influenced by external factors. One such factor is likely the manner in which the HF diagnosis is relayed to the patient by health care professionals. © 2016 Selan et al.