During 1992, the Research Committee of the Weed Science Society of America (WSSA) prepared a list of research needs for the discipline of weed science. The identified needs fit well with the recommendations of the Future Directions for Weed Science Symposium held in Washington D.C. on April 15, 1993, thus are provided as a supplement to the Symposium publication. The Research Committee concluded weed science research should focus on increasing knowledge related to the economic and biological impact of weeds across a wide variety of environments (crop production, forestry, right-of-way and aquatic). An increased understanding of the biology, ecology and genetics of weeds is needed to optimize their management. Research on control of weeds with biological agents and natural products should be conducted with emphasis on optimizing performance in the field environment. The development of weed populations resistant to chemical and biological control agents should be studied so the occurrence of such populations can be minimized. Because herbicides will continue to be the primary basis of weed management for the foreseeable future, research is needed to optimize herbicide application technology and to minimize their impact on the environment, particularly related to surface and groundwater contamination. Finally, new and reliable methods to detect herbicide residues in water, soil and vegetation are needed.