OBJECTIVES: The purpose of this study was to determine whether statin treatment is effective and safe in very elderly (80 years and older) acute myocardial infarction (AMI) patients. BACKGROUND: Elderly individuals constitute an increasing percentage of patients admitted to hospitals for AMI. Despite that these patients have a higher mortality risk, the application of evidence-based medicine remains much lower than for younger patients. METHODS: We included all patients 80 years and older who were admitted with the diagnosis of AMI in the Register of Information and Knowledge About Swedish Heart Intensive Care Admissions between 1999 and 2003 (n = 21,410). Of these, complete covariate and follow-up data were available for 14,907 patients (study population A). To limit the bias related comorbidity on statin therapy, we also performed analyses excluding patients who died within 14 days of the acute event (study population B) and all patients who died within 365 days (study population C). A propensity score was used to adjust for initial differences between treatment groups. RESULTS: All-cause mortality was significantly lower in patients receiving statin treatment at discharge in study population A (relative risk: 0.55, 95% confidence interval: 0.51 to 0.59), in study population B (relative risk: 0.65; 95% confidence interval: 0.60 to 0.71), and in study population C (relative risk: 0.66; 95% confidence interval: 0.59 to 0.76). Similar observations were made for cardiovascular mortality as well as for AMI mortality. There was no increase in cancer mortality in statin-treated patients. CONCLUSIONS: Statin treatment is associated with lower cardiovascular mortality in very elderly post-infarction patients without increasing the risk of the development of cancer.