Two principal mosquito breeding problems that occur in Florida are discussed from the standpoint of a manager of a mosquito abatement district: 1) mosquitoes that breed in standing or permanent water, and 2) mosquitoes that breed in temporary habitats such as floodwater pools. The efficacies of several different types of biological control agents are discussed for each type of problem. Fish are used in permanent water sites, and several other organisms are being evaluated. No programs are based exclusively on biological control agents. Biological control is generally not used in temporary sites. Relative costs of chemical and biological control are discussed. [References: 6]