An integrated approach for the control of mosquitoes and the diseases they transmit will better enable sustainable control while helping to circumvent some of the problems associated with the use of conventional insecticides. Environmental methods and biological control are alternatives to chemical control and are key components of the integrated strategy. The use of vertebrate and invertebrate predators and entomopathogens as biological control agents and their role in integrated control programs is reviewed with emphasis on fish, Toxorhynchites mosquitoes, Notonecta species, predatory copepods, entomopathogenic bacteria, and the fungus Lagenidium giganteum. The successful implementation of these organisms will depend on an in-depth understanding of the ecology of both the targeted species and the biological control agents to be used. Thorough geographic reconnaissance will also be essential for the successful abatement of pest and vector mosquitoes. The success and sustainability of future programs, especially in developing countries, will rely not only on the use of the most appropriate technologies but also on the direct participation of the affected communities. Possible undesirable effects of biological control are also reviewed.