The Science and Technology Task Group (the Task Group) attempted to address four questions: 1) Is there a need for watershed planning in Ontario?; 2) What is state-of-the-art science in watershed planning?; 3) Is state-of-the-art science being applied to watershed planning in Ontario?; and, 4) What are the most critical areas of need for improving the science for watershed planning and the application of science to watershed planning in Ontario? This report summarizes the findings of the Science and Technology Task Group with respect to state-of-the-art science as it relates to watershed planning, its relevance and application in Ontario. It is based on information from a number of sources: experience of members, review of literature, interviews and discussions with technical and scientific experts, and feedback obtained from participants at a workshop attended by representatives from the research, practitioner, and academic communities.