The Atlantic Forest is a biome of great diversity under constant anthropic pressure. This study was conducted in three environments in the state of Rio de Janeiro: rural environment, Seropédica campus (UFRRJ); urban environment, Urca campus (UNIRIO); and forest environment, Três Picos State Park, Cachoeiras de Macacu. We aimed to evaluate the attractiveness of the fauna of Calliphoridae and Mesembrinellidae by two stages of bait decomposition, study their synantropy, and identify bioindicators for each environment. Four traps were installed at each environment, two containing preserved beef liver and two containing beef liver with 48 h of putrefaction. Samples were collected quarterly, between June 2021 and May 2023. A total of 5476 dipterans were collected, with five Calliphoridae species (77.1%) and 11 Mesembrinellidae (22.9%). Laneella nigripes showed a preference for liver baits with 48 h of putrefaction. Mesembrinellidae species, Hemilucilia benoisti and Paralucilia nigrofacialis were asynanthropic, occurring exclusively in the forest environment. Hemilucilia segmentaria and H. semidiaphana were also asynanthropic, but occurred in urban and/or rural environments. Chrysomya and Cochliomyia genera and Lucilia cuprina were synanthropes. Eight potentially bioindicator species were identified for the forest environment and four for rural environments.