Insect diversity and abundance in the field pilot-scale swine and poultry waste lagoons were related to the organic pollution level of the lagoon water. Insect diversity was lowest in lagoons with high levels of organic pollution (ca. supernatant COD = 2000 mg/1, TOC = 1000 mg/1 and TKN = 500 mg/1 or higher). Shore flies, Brachydeutera argentata Walker, moth flies, Psychoda alternata Say and P. cinerea Banks, and rat-tailed maggots, Eristalinus aeneus (Scopoli) were the only insects found in these highly polluted lagoons. Mosquitoes, Culex quinquefasciatus Say, were not present in the lagoons with the highest levels of organic pollution but were the predominant insects in all other lagoons. Cx. quinquefasciatus were most abundant in lagoons with intermediate pollution levels (ca. supernatant COD =600 mg/1, TOC= 250 mg/1 and TKN = 175 mg/1 for swine lagoons and COD = 650-950 mg/1, TOC = 250-450 mg/1 and TKN = 165 mg/1 for poultry lagoons). Midges, Chironomus sp., predaceous water beetles, Tropisternus sp., backswimmers and water boatmen, present in small numbers, appeared to be tolerant of only low to intermediate levels of organic pollution (ca. supernatant COD = 1000 mg/1, TOC = TOC = 500 mg/1 and TKN = 400 mg/1 or less). Insect control by manipulating the organic pollution level of the lagoon water is discussed.