Abstract Background Current implantable cardioverter-defibrillator (ICD) guidelines do not impose age limitations for ICD implantation (IMPL) and generator exchange (GE); however, patients (pts) should be expected to survive for 1 year. With higher age, comorbidity and mortality due to non-sudden cardiac death increase. Thus, the benefit of ICD therapy in elderly pts remains unclear. Mortality after ICD IMPL or GE in pts ≥ 75 years was assessed. Methods Consecutive pts aged ≥ 75 years with ICD IMPL or GE at the University Hospital Cologne, Germany, between 01/2013 and 12/2017 were included in this retrospective analysis. Results Of 418 pts, 82 (20%) fulfilled the inclusion criteria; in 70 (55 = IMPL, 79%, 15 = GE, 21%) follow-up (FU) was available. The median FU was 3.1 years. During FU, 40 pts (57%) died (29/55 [53%] IMPL; 11/15 [73%] GE). Mean survival after surgery was 561 ± 462 days. The 1‑year mortality rate was 19/70 (27%) overall, 9/52 (17%) in pts ≥ 75 and 10/18 (56%) in pts ≥ 80 years. Deceased pts were more likely to suffer from chronic renal failure (85% vs. 53%, p = 0.004) and peripheral artery disease (18% vs. 0%, p = 0.02). During FU, seven pts experienced ICD shocks (four appropriate, three inappropriate). In primary prevention (n = 35) mortality was 46% and four pts experienced ICD therapies (two adequate); in secondary prevention (n = 35) mortality was 69% (p = 0.053) with three ICD therapies (two adequate). Conclusion Mortality in ICD pts aged ≥ 80 years was 56% at 1 and 72% at 2 years in this retrospective analysis. The decision to implant an ICD in elderly pts should be made carefully and individually.