Background Although the short-term benefit of primary percutaneous coronary intervention (PCI) in elderly patients with ST-elevation myocardial infarction (STEMI) has been demonstrated, the final long-term survival benefit is as yet unknown. Aim To assess the final survival benefit of primary PCI as compared to thrombolytic therapy in patients over 75 years of age. Methods Patients > 75 years with STEMI were randomised to either primary PCI or thrombolysis. Long-term data on survival were available for all patients. Results A total of 46 patients were randomised to primary PCI, 41 to thrombolysis. There were no significant differences in baseline variables. After a maximum of 20 years' follow-up, all patients had passed away. The patients randomised to thrombolysis died after a mean follow-up duration of 5.2 years (SD 4.9) compared to 6.7 years (SD 4.8) in patients randomised to primary PCI (p = 0.15). Thus, the mean final survival benefit of primary PCI was 1.5 years. Conclusion The final survival benefit of primary PCI as compared to thrombolysis in elderly patients with STEMI is 1.5 years and their life expectancy increases by 28.8%.