Abstract： Background:The comparative outcomes of subcutaneous implantable cardioverter-defibrillator (S-ICD) and transvenous ICD (T-ICD) have not been well studied.The aim of this study was to evaluate the safety and efficacy of currently available S-ICD and T-ICD.Methods:The study included 86 patients who received an S-ICD and 1∶1 matched to those who received single-chamber T-ICD by gender,age,diagnosis,left ventricular ejection fraction (LVEF),and implant year.The clinical outcomes and implant complications were compared between the two groups.Results:The mean age of the 172 patients was 45 years,and 129 (75％) were male.The most common cardiac condition was hypertrophic cardiomyopathy (HCM,37.8％).The mean LVEF was 50％.At a mean follow-up of 23 months,the appropriate and inappropriate ICD therapy rate were 1.2 ％ vs.4.7％ (x2 =1.854,P =0.368) and 9.3 ％ vs.3.5 ％ (x2 =2.428,P =0.211) in S-ICD and T-ICD groups respectively.There were no significant differences in device-related major and minor complications between the two groups (7.0％ vs.3.5％,x =1.055,P=0.496).The S-ICD group had higher T-wave oversensing than T-ICD group (9.3％ vs.0％,x2=8.390,P =0.007).Sixty-five patients had HCM (32 in S-ICD and 33 in T-ICD).The incidence of major complications was not significantly different between the two groups.Conclusions:The efficacy of an S-ICD is comparable to that of T-ICD,especially in a dominantly HCM patient population.The S-ICD is associated with fewer major complications demanding reoperation.