Background: The objective of this study was to determine whether the use of statins prevents the progression of ischemic heart disease (IHD) in patients with low levels of low-density lipoprotein cholesterol (LDL-C). Methods:We reviewed data obtained from IHD patients who underwent first percutaneous coronary intervention (PCI). Patients underwent follow-up coronary angiography (re-CAG) after PCI. However, only patients with LDL-C levels less than 100 mg/dL at PCI were included in this study. Ultimately, 92 patients were enrolled. All patients were divided into two groups: 1) patients who were treated with statins (n = 69), and 2) patients who were not treated with statins (n = 23). Results: The two groups had similar LDL-C levels at PCI. At re-CAG, the ratio of patients who underwent PCI for de novo lesion in the statin group was lower than that in the non-statin group (12% vs. 48%) (p < 0.001). In multiple regression analysis, statin usage and LDL-C level at PCI were independent predictors of the ratio of patients undergoing PCI for de novo lesion. Conclusions: Statins therapy for patients whose LDL-C levels are less than 100 mg/dL has a beneficial effect on secondary prevention of IHD.