Cognitive dysfunction is common in patients with heart failure (HF). Despite the high prevalence and the adverse associations of cognitive dysfunction in HF, the prognostic implications remain poorly understood. We sought to determine the influence of cognitive dysfunction, identified using the Montreal Cognitive Assessment (MoCA), on 180-day cardiovascular events. We analyzed data on 246 participants in an observational cohort study of adults with HF. The interview-format MoCA was administered to all participants. Time to first cardiovascular event was assessed as a cumulative end point during the 180 days after enrollment. Cox proportional hazards model was used for analysis of time to first event. The MoCA score was <26 for 91 patients (37%). Patients with a MoCA score <26 were more likely to have a cardiovascular event at 180 days. MoCA score <26 remained an independent predictor of cardiovascular event risk at 180 days when adjusted for the Seattle Heart Failure Model Score and the Charlson comorbidity index (hazard ratio 1.7, 95% confidence interval 1.1 to 2.6, p = 0.03). In conclusion, in patients with HF, cognitive dysfunction identified with a MoCA score of <26 is associated with increased risk of cardiovascular events at 180 days.