This paper takes the overall trade balance and bilateral trade balance as the external explanatory and also uses the unemployment rate and real GDP growth rate as the domestic explanatory variables. The result of estimation indicates that the unemployment rate and the overall trade balance affected the U.S. ITC`s antidumping investigation decisions. As the unemployment rate and the deficit of the overall trade balance increased, the number of the investigation of antidumping duties against the Korean exports appears to increase in the United States. Although this paper expects that the more is the deficit of bilateral trade balance, the more would be the number of antidumping investigation, the result of the estimation indicates that the bilateral trade balance and real GDP growth rate didn`t affect the United States` antidumping investigation decision. Consequently, the determinants of the United States` antidumping investigation decision are revealed to be the unemployment and the overall trade balance. There are certain shortcomings in the current paper. This paper covers 23 years only. The method of the empirical works was restricted to simple OLS. This paper used only the major macroeconomic variables to analyze the case of antidumping investigation against the Korean exports. Future works are needed to include various other variables as the explanatory variables.