Lactic acid bacteria are known to exert various physiologic functions in humans. In the current study, we investigated the effects of SoyproTM, a new soymilk fermented with lactic acid bacteria, like Leuconostoc kimchii, Leuconostoc citreum, and Lactobacillus plantarum, isolated from Kimchi, on adipocyte differentiation in preadipocyte 3T3-L1 cell lines and weight gain or the plasma lipid profile in Sprague-Dawley rats. Adipocyte 3T3-L1 cells treated with SoyproTM (10 μg/ml) significantly reduced the contents of cellular triglyceride and inhibited cell differentiation by Oil red O staining. Treatment with SoyproTM (10 μg/ml) for an additional two days in adipocytes inhibited the expression of peroxisome proliferator-activated receptor-μ2 and CCAAT/enhancer binding protein-α, transcription factors of adipocyte differentiation. Based on these in vitro studies, we examined the anti-obesity effect of SoyproTM in rats for six weeks. SoyproTM had no significant effect on high-fat diet-induced increases in body weight, food intake, or feed gain ratio. However, the administration of SoyproTM significantly reduced the concentration of the plasma low density lipoprotein cholesterol. Changes in the plasma levels of total cholesterol and glucose were inclined to decrease in SoyproTM administrated groups compared with saline treated group. Triglyceride and high density lipoprotein cholesterol values in SoyproTM fed groups were similar compared to those of saline fed groups. Although further research is needed, these findings suggest that SoyproTM decreased the levels of low density lipoprotein cholesterol in high-fat diet-induced obesity and might partially inhibit the adipocyte differentiation through the suppression of a transcription factors peroxisome proliferator-activated receptor-μ2 and CCAAT/enhancer binding protein-α.