Objective: To examine the potential impact of β-blockers and angiotensin-converting enzyme (ACE) inhibitors, medications which modulate β-adrenergic signaling, on immune function in patients with chronic heart failure (HF). Methods: 118 patients attending an HF center were tested for circulating levels of norepinephrine (NE), T cells and the inflammation-associated cytokine interleukin 6 (IL-6). Levels of the cytokines interferon-γ (IFNγ), IL-10, and tumor necrosis factor-α (TNFα) produced by cultured peripheral blood mononuclear cells (PBMC) were measured in culture supernatants following T cell stimulation in vitro. Results: NE levels were significantly lower in patients receiving ACE inhibitors (p = 0.0263), with a trend toward lower NE in patients receiving β-blockers. All patients exhibited relatively normal levels of T cells, and there was a trend toward higher levels of total (CD3+) and helper (CD4+) T cells (p = 0.0578 and 0.0932, respectively) in patients receiving either type of medication. The ratios of Th1 (IFNγ) to Th2 (IL-10) cytokines were lower in patients receiving a combination of β-blocker and ACE inhibitor therapy (p = 0.0373). NYHA class was a significant predictor of serum IL-6 (p < 0.0001). There was a trend toward lower levels of serum IL-6 in patients receiving both types of medications (p = 0.0606). TNFα production by CD3/CD28-stimulated PBMC was significantly lower in patients receiving ACE inhibitor medications (p = 0.0223). Conclusions: These results suggest that high sympathetic tone associated with chronic HF affects Th1/Th2 and inflammatory cytokine production, and that these effects can be modulated by medications. In addition to improvement in clinical parameters relating to cardiovascular function, β-blocker and ACE inhibitor medications also appear to have a beneficial effect on the immune system in HF.