To assess the impact of training resource-poor maize farmers on the Pacific Plain of Nicaragua in the use of integrated pest management (IPM), 1,200 farmers received training during two years. CARE trained 13 extensionists and they provided intensive training to 60 promoter-farmers, who trained the 1,200 farmers. The farmers were trained in: the dangers of pesticides, recognition of the important organisms (pests and beneficials) in their fields, the biology and ecology of the organisms, how to determine pest population levels, how to choose the best method and product for control, and how to make decisions in the fields according to their new understanding and simple cost-benefit analysis. Three groups of farmers were monitored for two years: the intensively trained farmers (60 promoter-farmers), the trained farmers (1,200), and a group of "control" farmers who did not receive training during the first two years. After two years, the trained farmers used fewer pesticides, spent less money on pest control, made higher net returns, and suffered less exposure to cholinesterase-inhibiting pesticides than did farmers who did not receive IPM training. In addition, a comparison of cholinesterase levels of farmers who used personal protective equipment showed no reduction of exposure to organophosphate insecticides, compared with farmers who did not use the equipment.