Probably all insects use semiochemicals; natural chemicals released by an organism that affect the behaviors of other individuals. Pheromones are intraspecific signals that aid in finding mates, food and habitat resources, warning of enemies, and avoiding competition. Interspecific signals known as allomones and kairomones have similar functions. The goals of using semiochemicals in pest management are (1) to monitor pest populations to determine if control is warranted and (2) to alter the behavior of the pest or its enemies to the detriment of the pest. In general, the advantages of using semiochemicals are (1) they have adverse effects only on target pests, (2) they are relatively nontoxic and required in low amounts, (3) they are nonpersistent and environmentally safe, and (4) they appear difficult for insects to develop resistance against. Monitoring of pest populations with pheromones is often integrated in management programs. However, successful control programs using semiochemicals as treatments have been mixed, likely due to the complexities of implementation. Problems include suboptimal semiochemical blends and release rates, poor dispenser and trapping efficiencies, inadequate coverage and extent of treatments, timing of applications, and a lack of understanding of the ecological processes. Examples of successful programs of direct control with semiochemicals are mainly on mating disruption in moths. Since pest insect ecologies appear varied, transferring knowledge from a system with successful control to another system may be difficult without major research efforts. Besides research in chemical ecology, development of simulation models may help our understanding of the importance of area-wide treatments and the major factors needed for successful use of semiochemicals.