It has often been assumed that the discovery of new insecticides will keep pace with resistance. However, escalation in the cost of developing new pest control agents, and the ever-increasing number of insect pests with strains resistant to even the most recently introduced insecticides indicate the need for strategies to prolong the effectiveness of existing materials and prevent the obsolescence of newly introduced chemicals. The rational development of such strategies must be based on a sound knowledge of resistance at the level of both the individual insect and the population, and be placed in the context of general pest control. This will need major multidisciplinary research programmes with well defined targets, the full cooperation of the pesticide industry, government regulatory agencies, and legislature and a change in attitude and habits of the user. Some of the problems in achieving these objectives are discussed.