Integrated weed management (IWM) is a component of integrated pest management (IPM), which is an interdisciplinary practice involving disciplines such as entomology, nematology, plant pathology, weed science, horticulture, agronomy, ecology, economics, and systems science. Most descriptions of IPM mention three elements: a) multiple tactics (for example, competitive varieties, cultural practices, herbicide usage) used in a compatible manner; b) pest populations maintained below levels that cause economic damage, and c) conservation of environmental quality. Integrated weed management was discussed in 1981 during a Weed Science Society of America (WSSA) Symposium entitled Integrated Weed Management Systems Technology for Crop Production and Protection. Topics presented included modeling weed biology, crop manipulation, biological control, herbicide technology, research needs, teaching approaches, and extension implementation. Our paper was presented as part of a symposium on IWM at the 1990 WSSA meeting. This paper describes some of the research that weed scientists have conducted during the past 40 yr. Topics examined include an introductory review of IPM, trends in several categories of weed research, goals and suggestions stated during the 1981 WSSA Symposium on IWM, IWM accomplishments since about 1981, and the future of IWM as a component of IPM.