This study analyzes the effects of knowledge characteristics on the extent of organizational effort for knowledge transfer. In this paper, three knowledge characteristics that affect organizational behavior for knowledge transfer are identified based on knowledge-based views and organizational learning theory: tacitness, difficulty, and the importance of knowledge. We establish three hypotheses on the effects of these three knowledge characteristics on the extent of effort for knowledge transfer (i.e., the frequency of contact with knowledge source), and provide empirical tests employing the dataset from project teams in a multinational consulting firm via the OLS model. Results show that tacitness, difficulty, and importance have positive effects on the frequency of contact with knowledge sources. This implies that firms exert more effort to acquire the knowledge when the knowledge is tacit, difficult, or important.