The author served as consultant to the Louisville/Jefferson County Board of Health from 1965 to 2004, identifying thousands of larval and adult mosquitoes. Reports on the occurrence of the 41 mosquito species identified during those years were submitted annually. Trends over the year are presented, with three species - Aedes vexans, Culex pipiens (complex), and Culex restuans - being consistently the dominant species. Other species came, went, or changed in relative abundance over those years.