A recent debate in sociological exchange theory concerns which form of exchange is likely to promote cohesion in exchange relations. One side maintains that bilateral exchange, often associated with economic transactions, entails joint action to share mutual benefits, contributing more to feelings of cohesion than do independent acts of unilateral giving from one person to another, typical of social exchange. The other side argues that bilateral exchange requires dividing resources under binding terms of exchange, which strains relationships by underscoring competitive aspects of exchange. The present study reconciles these divergent claims by testing a new model of exchange that combines key propositions from past theories to specify when bilateral exchange promotes or undermines cohesion. Results from two laboratory experiments provide support for the model’s core claim that cooperative forms of bilateral exchange can reinforce cohesion more than unilateral exchange does, contrary to the enduring assumption that economic exchange undermines relational bonds.