Background: Several randomized, controlled trials show that angiotensin -conve rting enzyme (ACE) inhibitors improve survival in patients who have had an acute myocardial infarction. However, existing data from trials do not address whethe r all ACE inhibitors benefit patients similarly. Objective: To evaluate whether all ACE inhibitors are associated with similar mortality in patients 65 years of age or older who have had an acute myocardial infarction. Design: Retrospective cohort study that used linked hospital discharge and prescription databases con taining information on 18 453 patients 65 years of age or older who were admitte d for an acute myocardial infarction between 1 April 1996 and 31 March 2000. Set ting: 109 hospitals in Quebec, Canada. Patients: 7512 patients who filled a pres cription for an ACE inhibitor within 30 days of discharge and who continued to r eceive the same drug for at least 1 year. Measurements: The association between the specific drugs and clinical outcomes was measured by using Cox proportional hazards models, with adjustment for demographic, clinical, physician, and hospit al variables and dosage categories, represented by time-dependent variables. Re sults: Enalapril, fosinopril, captopril, quinapril, and lisinopril were associat ed with higher mortality than was ramipril; the adjusted hazard ratios and 95%C Is were 1.47 (95%CI, 1.14 to 1.89), 1.71 (CI, 1.29 to 2.25), 1.56 (CI, 1.13 to 2.15), 1.58 (CI, 1.10 to 2.82), and 1.28 (CI, 0.98 to 1.67), respectively. The a djusted hazard ratio associated with perindopril was 0.98 (CI, 0.60 to 1.60). Li mitations: The administrative databases did not contain detailed clinical inform ation, and unmeasured factors associated with a patients risk for death may ha ve influenced physicians’prescription choices. Conclusion: Survival benefits in the first year after acute myocardial infarction in patients 65 years of age or older seem to differ according to the specific ACE inhibitor prescribed. Ramipr il was associated with lower mortality than most other ACE inhibitors. Background: Several randomized, controlled trials show that angiotensin -converting enzyme (ACE) inhibitors improve survival in patients who have had an acute myocardial infarction. However, existing data from trials do not address whethe r all ACE inhibitors benefit patients similarly. Objective: To evaluate whether similar ACE inhibitors are associated with similar closely in in patients 65 years of or older who have had an acute myocardial infarction. Design: Retrospective cohort study that used linked hospital discharge and prescription databases con taining information on 18 453 patients 65 years of age or older who were admitting d for an acute myocardial infarction between 1 April 1996 and 31 March 2000. Set ting: 109 hospitals in Quebec, Canada. Patients: 7512 patients who filled a cript for an ACE inhibitor within 30 days of discharge and who continued to r eceive the same drug for at least 1 year. Measurements: The association between the specific drugs and clinical out comes was measured by using Cox proportional hazards models, with adjustment for demographic, clinical, physician, and hospit al variables and dosage categories, represented by time-dependent variables. Re sults: Enalapril, fosinopril, captopril, quinapril, and lisinopril were associat ed the adjusted hazard ratios and 95% C Is were 1.47 (95% CI, 1.14 to 1.89), 1.71 (CI, 1.29 to 2.25), 1.56 (CI, 1.13 to 2.15), 1.58 (CI, 1.10 to 2.82), and 1.28 (CI, 0.98 to 1.67), respectively. The a djusted hazard ratio associated with perindopril was 0.98 (CI, 0.60 to 1.60). Li mitations: The administrative databases did not contain detailed clinical informtion, and unmeasured factors associated with a patient’s risk for death may ha ve influenced physicians’ prescription choices. Conclusion: Survival benefits in the first year after acute myocardial infarction in patients 65 years of age or older seem to differ according to the specific ACE inhibitor prescr ibedRamipr il was associated with lower mortality than most other ACE inhibitors.