Throughout the life-cycle of a design project, architects rely heavily on their tacit design knowledge to support design decisions. Tacit knowledge is highly personal and implicit. As such, it encompasses expertise, intuitive understanding, and professional insight formed as a result of experience. Due to its implicit nature, tacit design knowledge is typically shared only among colleagues who work in the same office through face-toface interactions. With emerging Computer-Mediated Communication (CMC) technologies, designers face new opportunities for capturing and reusing tacit design knowledge. However, there is no accepted CMC strategy for sharing tacit design knowledge in the Architecture, Engineering, and Construction (AEC) industry. This research investigates the impact of tacit design knowledge on design performance in a distributed design environment supported by CMC software. The software was developed and tested in three design studios in which design students sought advice from experts in remote locations. It provides tools for showing images, such as drawings and renderings, and for engaging in a written dialogue (chat session). The written and graphic artifacts of the conversation are stored in a Web-accessible database. The chat sessions included the identification, clarification, and explanation of real problems. Dialogue records provide evidence of a significant influence upon the students’ approach to conceptual design. Content analysis of the comments from the experts provides qualitative evidence for the software’s effectiveness. The participants shared past experience, professional recommendations, and intuitive expectations. In follow-up surveys, most participants reported that their experience with the software was very enjoyable and the software is well-designed to support sharing of design knowledge. This research also suggests that tacit design knowledge may be confidently captured and shared through careful strategic implementation of CMC technology in a distributed design environment. Demographic and attitudinal surveys of the participants suggest that enabling factors for sharing tacit design knowledge include knowledge sharing attitude, just-in-time expertise matching, and timing of the communication.