In order to develop a functionally improved kochujang with antiobesity effects, garlic-added kochujang was prepared with freeze-dried garlic powder and followed by fermentation for 60 days at $30^{circ}C$. Antiobesity effect of the garlic-added kochujang was investigated by measuring the leptin secretions and mRNA expression levels of obesity-related gene such as TNF${alpha}$, PPAR${gamma}$, C/EBP${alpha}$, and SREBP1c, in cultured 3T3-L1 adipocytes. Fermentation of garlic-added kochujang led to decreased levels of leptin secretions and reduced the mRNA expression levels of TNF${alpha}$, PPAR${gamma}$, C/EBP${alpha}$, and SREBP1c in the 3T3-L1 adipocytes. Accordingly, these results suggest that the addition of garlic to kochujang has a potential as a valuable functional food for controlling obesity.