Abstract Background The percentage of elderly treated with percutaneous coronary intervention (PCI) has been increasing year by year. Little is known about predictors of hospital mortality in elderly undergoing PCI for acute coronary syndromes (ACS) and stable angina. Methods Between 2005 and 2008 a total of 47,407 consecutive patients undergoing PCI were prospectively enrolled into the PCI-Registry of the EHS Programme. For the present analysis patients were divided into four categories: ACS patients ≥ 75 (n = 4,943) and < 75 years (n = 19,446), and patients with stable angina ≥ 75 (n = 3,393) and < 75 years (n = 19,625). A multiple logistic regression analysis was conducted to detect independent predictors of mortality in patients ≥ 75 years undergoing PCI. In addition, differences in clinical characteristics, procedural details and in-hospital outcomes between the subgroups were evaluated. Results Patients ≥ 75 years had more co-morbidities, and more severe coronary pathology. The use of guideline-recommended adjunctive therapy and procedural success was high in all groups. The incidence of in-hospital death was highest in ACS patients ≥ 75 years (5.2%) and < 75 years (1.7%), followed by patients with stable angina ≥ 75 (0.5%) and < 75 years (0.2%). Haemodynamic instability and acute ST-elevation myocardial infarction were the strongest determinants of hospital mortality among patients ≥ 75 years with ACS, whereas interventional complications were the most meaningful predictors of death in older patients undergoing elective PCI. Conclusions Patients ≥ 75 years undergoing PCI face a relatively low risk of hospital death. However, complication rates were significantly higher compared to younger patients, strongly influenced by clinical, angiographic and interventional variables.