BACKGROUND: More data regarding effects of glucagon-like peptide-1 receptor agonists in patients with type 2 diabetes (T2D) and heart failure (HF) are required. OBJECTIVES: The purpose of this study was to investigate the effects of liraglutide on cardiovascular events and mortality in LEADER (Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results) participants, by HF history. METHODS: In the multinational, double-blind, randomized LEADER trial, 9,340 patients with T2D and high cardiovascular risk were assigned 1:1 to liraglutide (1.8 mg daily or maximum tolerated dose up to 1.8 mg daily) or placebo plus standard care, and followed for 3.5 to 5 years. New York Heart Association (NYHA) functional class IV HF was an exclusion criterion. The primary composite major adverse cardiovascular events outcome was time to first occurrence of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke. Post hoc Cox regression analyses of outcomes by baseline HF history were conducted. RESULTS: At baseline, 18% of patients had a history of NYHA functional class I to III HF (liraglutide: n = 835 of 4,668; placebo: n = 832 of 4,672). Effects of liraglutide versus placebo on major adverse cardiovascular events were consistent in patients with (hazard ratio [HR]: 0.81 [95% confidence interval (CI): 0.65 to 1.02]) and without (HR: 0.88 [95% CI: 0.78 to 1.00]) a history of HF (p interaction = 0.53). In both subgroups, fewer deaths were observed with liraglutide (HR: 0.89 [95% CI: 0.70 to 1.14] with HF; HR: 0.83 [95% CI: 0.70 to 0.97] without HF; p interaction = 0.63) versus placebo. No increased risk of HF hospitalization was observed with liraglutide, regardless of HF history (HR: 0.98 [95% CI: 0.75 to 1.28] with HF; HR: 0.78 [95% CI: 0.61 to 1.00] without HF; p interaction = 0.22). Effects of liraglutide on the composite of HF hospitalization or cardiovascular death were consistent in patients with (HR: 0.92 [95% CI: 0.74 to 1.15]) and without (HR: 0.77 [95% CI: 0.65 to 0.91]) a history of HF (p interaction = 0.19). CONCLUSIONS: Based on these findings, liraglutide should be considered suitable for patients with T2D with or without a history of NYHA functional class I to III HF. (Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results [LEADER]; NCT01179048).