Many observers see mutual distrust as a major reason for increasing tensions in East Asia, but few studies systematically exploreexactly how trust, or the lack of it, influences international cooperation in the region. We examine the microfoundations of internationaltrust in East Asia by analyzing an original survey of Chinese urban residents' attitudes toward Japan and SouthKorea. We find that generalized trust, or the belief that other nations have benign intentions, provides the most important drivingforce of trust toward Japan and South Korea. This, in turn, has a positive effect on preferences for interstate cooperation.We also find that, contrary to conventional wisdom, nationalism and historical memory have little or no effect on internationaltrust. Our analysis enhances our broader understanding of international trust by clarifying its sources and consequences. It alsosuggests some important policy implications for Sino-Japanese relations and Chinese foreign policy.