Eight isolations of three arboviruses were made from mosquitoes collected in Indiana during 1978-80. With the seven isolations made prior to 1966, the total number of virus isolates from mosquitoes in this state is now 15. Flanders virus has been isolated six times, St. Louis encephalitis and Trivittatus (TVT) viruses three times each, LaCrosse (LAC) virus twice and Bunyamwera group virus (probably Cache Valley virus) once. This is the first report of LAC and TVT virus isolations from mosquitoes in Indiana.