OBJECTIVES: To assess the utilization of secondary preventive medications after an acute myocardial infarction (AMI) in a state Medicaid population.  METHODS: The study was a retrospective cohort analysis using a state Medicaid claims database.  The study cohort was identified based on inpatient claims for discharges with either a primary or secondary diagnosis code for AMI (ICD-9 code: 410.XX) between January 1, 2002 and December 31, 2006.  The study cohort was restricted to patients who were < 65 years old and were enrolled in the traditional fee-for-service program.  Utilization of secondary preventive medications was considered appropriate if patients filled at least 1 prescription for each of the recommended medications (angiotensin-converting enzyme (ACE) inhibitors /angiotensin-receptor blockers, beta-blockers, and statins) in the 90 days after discharge.  Logistic regression analysis was used to identify demographic and clinical predictors associated with the recommended utilization of secondary preventive medications. RESULTS: The final study cohort consisted of 752 patients discharged following hospitalization for AMI. The mean age of the cohort was 53±7.9 years and there were a higher proportion of females (59%) and whites (84.6%) in the study sample.  Only 43.25% of the patients appropriately utilized all the recommended medications after AMI.   Regression analysis indicated that use of percutaneous transluminal coronary angioplasty (PTCA) procedures during the hospitalization (OR =2.64; 95% CI:1.78 – 3.89); having a diagnosis of hyperlipidemia (OR=1.71; 95% CI:1.17 –2.51), hypertension (OR=2.00; 95% CI:1.18 – 3.39) or asthma (OR=0.56; 95% CI:0.37 – 0.87); and utilization of the recommended medications prior to hospitalization (OR=2.42;95% CI:1.30 – 4.50) were significant predictors of appropriate utilization of secondary preventive medications. CONCLUSIONS: Post-AMI patients in a state Medicaid program had sub-optimal utilization of secondary preventive medications; however, the utilization rates were higher than in previous studies that primarily focused on an older cohort of patients.