Does exchange, i.e., vote trading, occur in legislatures?!f so, is it quantitatively important or optimal? How important are political parties for the organization of logrolling coalitions? To address these questions, this paper investigates a broad range of votes where logrolling has been reported among interests favoring subsidies for urban, labor, and farm interests. The findings suggest that logrolling agreements are widespread, that many Democratic congressmen changed votes because of logrolling agreements, and that the Democratic party served to facilitate logrolling between its members. Furthermore, logrolling coalitions exhibited a strong degree if stability.