An ecological risk assessment focused on six common mosquito adulticides, including four pyrethroids (sumithrin, resmethrin, pyrethrins, and permethrin) and two organophosphates (malathion and naled), and two larvicides (methoprene and Bacillus thuringiensis israelensis (Bti)). Piperonyl butoxide, a synergist for the pyrethroids, was also assessed. Both aquatic and terrestrial non-target organisms were considered for acute and chronic exposures to the adulticides. Tier I exposure estimates were derived from ISCST3, AERMOD for deposition and air concentrations affecting terrestrial organisms and PRZM-EXAMS for standard pond concentration affecting aquatic organisms. Non-targets exposed to adulticides included rodents, birds, as well as aquatic vertebrates and invertebrates in a pond subject to receiving the chemical via drift and runoff. Non-targets exposed to larvicides included aquatic vertebrates, and invertebrates in a pond to which the chemical was applied. None of the chemicals breached a regulatory level of concern for acute and chronic exposures in either environment for endangered and non-endangered species. Two field experiments were conducted from 2004 through 2006 to measure the acute aquatic effects of sumithrin, permethrin, methoprene, and Bti, and chronic terrestrial effects of permethrin. No significant treatment effects were observed for population abundance, species diversity, species richness, or species evenness in either the acute aquatic study or the chronic terrestrial study.