Recurrence of myocardial infarction, especially when occurring early after the prior one, carries a significant morbidity and mortality rate. The aim of this study was to investigate the characteristics of patients who experienced recurrence under secondary prevention therapy. Case record review identified myocardial infarction patients who had a history of previous myocardial infarction within 5 years. Hospital chart records, initial laboratory data, medications, and type of infarction were reviewed. Patients were divided into two groups according to the interval of recurrence: an early group (recurrence within 1 year), and a late group (recurrence after more than 1 year). A total of 89 patients were included in the analysis; 40 patients in the early group, and 49 patients in the late group. Mean age in the early group and late groups was 67.3 +/- 11.9 and 59.4 +/- 8.9, respectively (P = 0.001). Mean body mass index in the early and late groups was 22.1 +/- 3.6 and 25.0 +/- 3.3, respectively (P < 0.001). There were fewer current smokers in the early group (7.5% vs 44.9%, P < 0.001) and more stent thrombosis (17.5% vs 2%, P = 0.02), as compared with the late group. The in-hospital mortality rate tended to be higher in the early group (7.5% vs 0%, P = 0.09). Multiple logistic regression revealed that smoking status (odds ratio [OR] 0.09, 95% confidence interval [CI] 0.02-0.49, P = 0.005), HDL cholesterol level (5 mg/dl increase: OR 1.34, 95% CI 1.04-1.74, P = 0.03), and stent thrombosis (OR 35.59, 95% CI 2.13-595.49, P = 0.01) had significant associations with early recurrence. Early recurrence of myocardial infarction was associated with stent thrombosis, a higher HDL cholesterol level, and a lower frequency of smoking. Early recurrence had a trend toward higher mortality than late recurrence.