Recent epidemiological analyses suggest that incident cancer may be more common among patients with preexisting heart failure (HF) than in patients without HF. Arguments against this notion have been the increased chance of co-occurrence of 2 high-prevalence conditions and increased tumor detection in patients with HF because of intensified medical observation. However, biological data lend support to the hypothesis that HF is an oncogenic condition. Neurohormonal activation has been related to cancer initiation, progression, and dissemination by studies not specifically focusing on HF, which are now reappraised in the light of the emerging evidence that tumors are diagnosed more often in HF than control cohorts. Furthermore, a thought-provoking scenario to be considered is that a systemically perturbed milieu, where low-grade inflammation plays a primary role, leads to both HF and malignancy, thus connecting 1 disease to another. Postischemic HF has been shown to promote tumor growth in an animal model. Exploring these and other pathways potentially linking HF to malignancy is a new and exciting field of research, with the ultimate goal of answering the question of whether HF does promote cancer.