This study is a quantitative research to explore researchers' tacit knowledge sharing behaviors of the Fisheries Research Institute in Taiwan. The goal is to enhance library's services to fisheries researchers through this understanding. The study has depth interviewed 16 researchers from different departments of the Institute. In addition, their relevant work documents such as laboratory diaries and project notes are also reviewed. The study shows that researchers' tacit knowledge is the knowledge of professional practice. Their sharing method mainly is direct communication through conference, meeting, and laboratory diaries and notes. The study found that the Institute lacks a systematic mechanism to display researchers' tacit knowledge. The importance of the transfer of tacit knowledge is not firmly recognized. Thus, the study suggests that creating specified groups and establishing environment for sharing tacit knowledge in the Institute are needed. Also, the Institute could enhance library's functions to become a fisheries knowledge management center in Taiwan.