A checklist of 63 species of mosquitoes endemic in New Jersey is presented. Although Aedes albopictus was included in the previous checklist, the species has dramatically increased its geographic range and population numbers in recent years, and it is now prevalent in 19 of New Jersey's 21 counties. The invasive Aedes japonicus japonicus is also now widespread throughout the state and is an addition to the previous checklist. Culex erraticus, an endemic species with a previous distribution primarily in the southern portion of the state, has also expanded its range significantly in New Jersey in recent years and is now detected state-wide. Mosquito control personnel periodically discover localized populations of Ae. aegypti, but the species fails to overwinter successfully in New Jersey and is not included on the checklist.