This paper studies transaction costs changes arising from the introduction of the Internet in transactions between firms. We divide transaction costs into coordination costs and motivation costs. We classify coordination efficiencies into three categories: process improvements, marketplace benefits, and indirect improvements. For motivation costs, we focus on informational asymmetries. We apply this framework to internal data from an Internet-based firm to measure process improvements, marketplace benefits, and motivation costs. Our results suggest potentially large process improvements and marketplace benefits. We find little evidence that informational asymmetries are more important in the electronic marketplace than in the existing physical ones.