This study develops and tests a model of information search in complex buying. We incorporate three categories of influences of organizational, personal and situational factors that affect information searching efforts. A sample of 96 of the largest Brazilian firms reported their use of the various influences in the decision to purchase integrated business management systems. Findings show that formalization of the organization is a key driver of information search efforts. Situational characteristics of importance, novelty and bargaining power increased the level of information search. Also, conformity of the purchasing agent and organizational centralization reduce information search efforts among the sampled Brazilian firms.