An outbreak of eastern equine encephalitis (EEE) occurred in the northeastern portion of the Dominican Republic during the later winter and early spring of 1978. No virus was isolated from 6,752 mosquitoes and 10,948 Culicoides collected in the affected area. Culex nigripalpus made up 72% of the mosquito catch, and no salt-marsh Aedes were collected. In view of the lack of EEE virus isolations from arthropods in the Dominican Republic during this and previous outbreaks, arthropod collection records may provide the strongest clues for selecting candidate vector species in the area. The collection data are summarized and discussed with this objective in mind.