Knowledge is the critical success factor for organizations to compete in the contemporary business world. Organizations that can make full use of their collective expertise and knowledge are likely to be more innovative, efficient and effective in the marketplace. With the development of advanced information and communication technology, organizations are undertaking various knowledge management initiatives to augment traditional ways of knowledge transfer. This dissertation intended to understand how various factors influence knowledge workers' knowledge sourcing behavior in the multimodal knowledge network. More specifically, our research question is: How do task characteristics, knowledge characteristics and individual characteristics influence knowledge workers' channel preferences during their knowledge sourcing activities?We built a knowledge sourcing preference model which predicts knowledge workers' preferences among various knowledge channels. We identified eight important antecedents from a wide spectrum of task characteristics, knowledge characteristics, and individual characteristics. We also identified three representative knowledge sourcing channels: face-to-face communication with colleagues, knowledge repositories, and discussion forums. We developed eight hypotheses on how each of the antecedent influence channel preferences.We tested our hypotheses through a survey we conducted in an international information technology company. Out of the eight hypotheses, the hypotheses on the influences from knowledge codifiability, knowledge volatility, extroversion/introversion dimension of the personality, and reciprocation wariness are supported. The hypotheses on the influences from task interdependency and task urgency are partially supported. The hypotheses on the influences from task routineness and expertise are not supported.This study furthers our understanding of knowledge workers' knowledge sourcing behavior in a multimodal knowledge network. The results of this study help organizations understand the advantages and disadvantages of various sourcing channels under certain circumstance of tasks, knowledge, and individuals. With this understanding, organizations will be able to have reasonable expectations on the utilization of knowledge transfer approaches, and to improve the effectiveness of the knowledge transfer initiatives. This will enable the organizations to cultivate environments or design systems to develop the types of channels to accommodate the preferences of knowledge workers with various combinations of tasks, knowledge and individual characteristics.