This study investigated the association between left ventricular ejection fraction (LVEF) and the risk of ventricular arrhythmias (VA), heart transplantation, and death in cardiac sarcoidosis (CS). We identified 110 CS patients meeting 2014 Heart Rhythm Society (HRS) diagnostic criteria with baseline LVEF <35% (n = 32) or ≥35% (n = 78). The primary end point was sustained VA or sudden cardiac death (SCD), and secondary end points included risk of heart transplantation, death, or a composite. Logistic regression determined risk factors for VA/SCD, and Cox proportional hazards regression analysis was performed for secondary end points. Receiver operating curve analysis determined the best discrimination point of LVEF for each end point; sensitivity analyses evaluated the effects of higher LVEF on each end point. Over a follow-up of 2.6 (range 1.0 to 5.8) years, 49 (44.5%) CS patients experienced VA/SCD, including 19 of 32 (59.4%) with LVEF <35%, and 30 of 78 (38.5%) with LVEF ≥35%. After adjustment, LVEF <35% was not significantly associated with an increased risk of VA/SCD compared with LVEF ≥35% (odds ratio 1.3, 95% confidence intervals 0.5 to 3.7). Although LVEF <35% was associated with an increased risk of heart transplantation and death (28.1% vs 12.8%, p = 0.05), this was not significant after adjustment (hazard ratio 1.7, 95% confidence intervals 0.5 to 9.0, p = 0.53). In conclusion, patients with CS experience high rates of VA, SCD, and heart transplantation, even when LVEF is mildly impaired or normal. Patients with LVEF <35% are at particularly elevated risk of VA/SCD. Our findings highlight the imperative to investigate arrhythmia risk in all patients with CS, even in the setting of an otherwise reassuring LVEF.