This paper identifies some of the priority research that is needed to accelerate integrated pest management (IPM) toward more sustainable crop protection in developing countries. Perhaps the most important need is for research that measures how different IPM tactics contribute to long-term crop stability. Another is for research that critically examines the interactions of different pest control tactics. Researchers especially need to reevaluate the widely accepted view that host plant resistance and biological control are naturally complementary. Experimental data and population genetics models have challenged this view. Researchers also need to reevaluate the view that botanical pesticides, which many developing countries are promoting, are harmless to nontarget organisms. Examples show that some formulations of neem pesticides may negatively affect natural enemies and aquatic organisms. Crops engineered for pest resistance offer new opportunities in future IPM programs in developing countries, but their use opens questions about ecological and human health effects. IPM researchers should team up with ecologists, health specialists, economists, and others and critically evaluate effects of the engineered plants before farmers start planting them widely. Although basic research is essential to answer questions concerning exploitation of IPM tactics for best long-term results, research that builds on farmer practice also is an important need in developing countries.