DeLone and McLean’s (1992) comprehensive review of different information system success measures concludes with a model of interrelationships between six IS Success constructs. This paper critically examines the meaning of four of these constructs and the evidence of relationships between them. It then provides results from an empirical test of these relationships. TheempiricalresultsprovidesubstantialsupportforDeLoneandMcLean’smodel. Threefactors,System Quality, Information Quality, and Usefulness, are found to explain 72% of the variance in the overall User Satisfaction measure. Three factors, System Quality, Information Quality, and a measure of the importance of the system to the user, User Involvement, are found to explain 56% of the variance in Usefulness. The paper concludes that of the four measures studied, the best “omnibus” measure of IS success is User Satisfaction. This can be measured using the simple four-question instrument presented in the study.