Background— Some patients with left ventricular systolic dysfunction (LVSD) have a dramatic improvement in left ventricular ejection fraction (LVEF) after β-blockade. No study has analyzed the long-term echocardiographic and clinical follow-up of this subgroup of patients. Methods and Results— We included in this analysis 174 consecutive patients with LVSD who had an LVEF≥45% after β-blockade. We performed a long-term echocardiographic follow-up (median 7.7 [4–9.9] years) and clinical follow-up (median 9.2 [7.2–10.8] years). LVEF improved from 33±8% to 54±6% after β-blockade ( P <0.0001). At the last echocardiographic evaluation, 26% of the patients had an LVEF<45% (mean±SD: 34±6%), whereas 74% still had an LVEF≥45% (mean±SD: 54±6%). Independent predictors of LVEF deterioration were a low LVEF, a high left ventricular end-diastolic diameter and a low heart rate after β-blockade, and the presence of a complete left bundle–branch block. In the overall study population, survival rates were 90% at 5 years and 75% at 10 years. Cardiovascular death rate was 9%, noncardiovascular death rate was 11%, and unknown death rate was 3%. Patients with subsequent LVEF deterioration had a higher cardiovascular mortality compared with patients with sustained recovered LVEF (22% versus 4%). Conclusions— The long-term survival of patients with LVSD and with near-normal LVEF after β-blockade is good. However, a quarter of these patients may experience a subsequent degradation of LVEF. These patients are at higher risk of cardiovascular mortality.