For patients admitted with worsening heart failure (HF), early follow-up after discharge is recommended. Whether outcomes can be improved when follow-up is done by cardiologists is uncertain. We aimed to determine the association between cardiology follow-up and risk of death for patients with HF discharged from hospital. Using data from the National Heart Failure Audit (England and Wales), we investigated the effect of referral to cardiology follow-up on 30-day and 1-year mortality in 68,772 patients with HF and a reduced left ventricular ejection fraction discharged from 185 hospitals from 2007 to 2013. The primary analyses used instrumental variable analysis complemented by hierarchical logistic and propensity-matched models. At the hospital level, rates of referral to cardiologists varied from 6% to 96%. The median odds ratio (OR) for referral to cardiologist was 2.3 (95% confidence interval [CI] 2.1 to 2.5), suggesting that, on average, the odds of a patient being referred for cardiologist follow-up after discharge differed ???2.3 times from one randomly selected hospital to another one. Based on the proportion of patients (per region) referred for cardiology follow-up, referral for cardiology follow-up was associated with lower 30-day (OR 0.70; 95% CI 0.55 to 0.89) and 1-year mortality (OR 0.81; 95% CI 0.68 to 0.95) compared with no plans for cardiology follow-up (i.e., standard follow-up done by family doctors). Results from hierarchical logistic models and propensity-matched models were consistent (30-day mortality OR 0.66; 95% CI 0.61 to 0.72 and 0.66; 95% CI 0.58 to 0.76 for hierarchical and propensity matched models, respectively). For patients with HF and a reduced left ventricular ejection fraction admitted to hospital with worsening symptoms, referral to cardiology services for follow-up after discharge is strongly associated with reduced mortality, both early and late.