Biological control scientists face imposing challenges and exciting opportunities in the next few years. Recently, public perceptions and demands have changed. Concerns about the environment, groundwater contamination by agricultural chemicals, worker safety, food purity, and sustainable agriculture have focussed attention on nonchemical pest control methods. While biological control of agricultural pests has had numerous successes, it is being challenged to rapidly and significantly increase its role in pest control and this will not be easy. Developing and implementing reliable, cost effective, and efficacious methods for controlling pests with parasites and predators requires that we improve organization of research programs, enhance research funding and infrastructure, and improve coordination between developmental research and technology transfer. Five questions are asked: Can we improve the success rate of classical biological control and expand its scope? Can we develop cost effective and high quality mass rearing methods for key parasites and predators as well as guidelines for their augmentative release? What rapid, predictive, and cost effective monitoring techniques can we use to optimize the reliability of biological control? How can we improve the conservation and compatibility of biological control agents with other pest control methods? How can we effectively, and rapidly, train farmers to use all the available biological control tactics? These questions must be answered, and soon, if biological control is to meet the challenge to become a dependable mainstream pest control strategy for U.S. agriculture by the year 2000.