Abstract Background: Current guidelines did not provide recommendations on indications of an additional implantable cardioverter-defibrillator (ICD) to patients receiving cardiac resynchronization therapy (CRT), and it still remains controversial due to lack of evidence from randomized controlled trials (RCTs). Method: PubMed, Embase and Cochrane CENTRAL from the inception to May 2020 were systematically screened for studies reporting on the comparison of CRT-defibrillator (CRT-D) and CRT-pacemaker (CRT-P), focusing on the adjusted hazard ratio (aHR) of all-cause mortality. We pooled the effects using a random-effect model. Results: Twenty-one studies encompassing 69919 patients were included in this meta-analysis. With no restriction to characteristics of including population, CRT-D was associated with a lower all-cause mortality compared with CRT-P significantly (aHR: 0.79, 95%CI: 0.72-0.88, I2=40.5%, P<0.0001). This mortality benefit was also observed in patients with ischemic cardiomyopathy (ICM) (HR: 0.74, 95%CI: 0.64-0.86, I2=0%, P＜0.0001). However, there is no significant difference in patients with non-ischemic cardiomyopathy (NICM) (HR: 0.91, 95%CI: 0.82-1.01, I2=0%, P=0.087), older age (age ≥75 years, aHR: 0.96, 95%CI: 0.83-1.12, I2=0%, P=0.610). Subgroup analysis was performed and indicated that there is no mortality benefit of CRT-D for primary prevention (aHR: 0.92, 95%CI: 0.74-1.14, I2=0%, P=0.444). Conclusion: After adjusted the differences in clinical characteristics, additional ICD therapy was associated with a reduced all-cause mortality in patients receiving CRT, especially in patients with ICM. However, our work suggested that additional ICD may not be applied to elderly, NICM patients or for primary prevention. Keyword: heart failure; cardiac resynchronization therapy; defibrillator; all-cause mortality; meta-analysis