Accumulating evidence indicates that inflammatory mediators are important in the pathogenesis of chronic heart failure (CHF), contributing to cardiac remodeling and peripheral vascular disturbances. Several studies have shown increased levels of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, and IL-6 in patients with CHF in both plasma and circulating leukocytes as well as in the failing myocardium itself. Importantly, this increase in inflammatory mediators does not seem to be accompanied by a corresponding increase in anti-inflammatory cytokines, such as IL-10 and transforming growth factor-beta, resulting in an inflammatory imbalance in the cytokine network. Traditional cardiovascular drugs seem to have little influence on the cytokine network in patients with CHF, and immunomodulatory therapy in addition to "optimal" cardiovascular treatment regimens has emerged as an option. Thus, several animal studies as well as some clinical pilot trials have suggested that downregulation of inflammatory cytokines may improve cardiac performance. On the other hand, preliminary results from placebo-controlled anti-TNF studies suggest no effect, or even an adverse effect of anti-TNF therapy on mortality and hospitalization. Although somewhat disappointing, these negative results do not necessarily argue against the cytokine hypothesis. These studies only underscore the difficulties and challenges in developing treatment modalities that can modulate the cytokine network in patients with CHF, resulting in anti-inflammatory and beneficial net effects. Further research in this area will have to more precisely identify the most important "actors" in the immunopathogenesis of CHF to improve the immunomodulatory treatment regimens in this disorder.