A temporal observational study was conducted with the aim of characterizing Culicidae richness, diversity, abundance, and species similarity in fragments of Atlantic Forest within the Itatiaia National Park, state of Rio de Janeiro, Brazil. A total of 31 mosquito species were collected in 2 sampling stations, during the day and night, and the abundance index and dominance coefficient for each species were calculated. The results showed that the culicid density was higher during the day, and the time preference was directly influenced by the climate variables analyzed, which acted as limiting factors for mosquito occurrence. The mosquito fauna at the Itatiaia National Park presented high richness, including some epidemiologically important species: Anopheles cruzii, Haemagogus leucocelaenus, Aedes scapularis, and Sabethes identicus. Studies of this region supply information on biodiversity, and consequently help to understand epidemiological aspects of potential pathogen vector species.