We provide an updated checklist of 67 endemic mosquito species known from Ontario, Canada. Nine endemic species are added to the checklist found in Darsie and Ward (2005) : Aedes cantator, Ae. churchillensis, Ae. nigripes, Ae. pullatus, Anopheles perplexens, An. crucians, An. smaragdinus, Culex erraticus, and Cx. salinarius. Only 4 specimens of Ae. albopictus have been recorded in Ontario since 2001 despite concerted efforts to find this species; therefore, it is considered an "accidental" species and is excluded from the checklist.
Keywords: Ontario; distribution; mosquito surveillance; new record.