Background: Left ventricular (LV) remodeling is a heterogeneous process, involving both infarcted and non-infarcted zones, which effects wall thickness and chamber size, shape and function. The objective of this study was to assess the associated factors of progressive LV dilatation during first 6 months after acute myocardial infarction (AMI). Methods: A total of 762 consecutive patients (63.3짹12 years, 546 males) with AMI, who were examined by echocardiography at admission and after 6 months. An increase in LV end-diastolic dimension index >10% was defined as a progressive LV dilation. They were divided into two groups according to the extent of progressive LV dilatation during 6 months: group I with progressive LV dilatation (n=132, 64.2 짹 11 years, 86 males) vs. group II without LV dilatation (n=630, 62.3 짹 12 years, 460 males). Various clinical, laboratory, echocardiographic parameters and coronary angiographic findings were compared between the two groups. Results: The rate of old age and female gender were higher in group I than in group II (p<0.05). The levels of glucose, creatinine, maximal creatine kinase (CK), troponin-T were significantly increased in group I than in group II (p<0.05) Increased left ventricle end diastolic and systolic dimension, low ejection fraction were more common in group I than in group II (p<0.001). The presence of dyslipidemia (odd ratio; 1.559, CI; 1.035-2.347, p=0.03) and low ejection fraction less than 45% (odd ratio; 3.328, CI 2.099-5.276, p<0.01) were significant independent predictors of progressive LV dilatation by multivariate analysis. Conclusions: Dyslipidemia and decreased systolic function affects LV remodeling process independently in patients with AMI.