Antidumping (AD) investigations are widespread. China and the US are two big users and targets of AD investigations. They, respectively, represent developing and developed countries on one hand, and new AD users and traditional AD users on the other. In this paper, using AD filing data of these two countries from 1991 to 2005, we explore whether China's AD is more retaliatory than that of the US. Our results obtained from negative binomial models with maximum likelihood techniques show that although both countries have some degree of retaliatory incentives in their AD filings, China is not more (or may even be less) retaliatory than the US. We also compare the two countries' similarities and differences in their AD responses to other factors such as macroeconomic conditions, contagions, and geographical distance.