Simple SummaryAedes aegypti,Ae albopictus,andCulex quinquefasciatus, three mosquito species of medical importance, were found coexisting in residential neighborhoods of urban and semiurban areas.Aedes aegyptiwas mostly present indoor houses compared toAe. albopictusandCx. quinquefasciatus. On the contrary, in cemeteries of the urban area,Ae. aegyptiwas found in lower densities compared toAe. albopictusandCx. Quinquefasciatus, which were the most abundant. The identification of these species and the knowledge of their distribution are essential for entomological surveillance in the prevention of outbreaks of vector-borne diseases.AbstractTapachula, Mexico, a tropical city, is an endemic area for dengue, in addition to several outbreaks in the last decade with chikungunya and zika. As part of the migratory corridor from Central to North America and the risks of scattered infectious diseases that this implies, the identification and distribution of potential disease vectors in and around residential areas are essential in terms of entomological surveillance for the prevention of disease outbreaks. The identification of mosquito species of medical importance coexisting in houses and cemeteries in Tapachula and two semiurban sites in southern Chiapas was investigated. Adult mosquitoes were collected from May to December 2018, resting inside and outside houses and in the tombstones and fallen tree leaves in cemeteries. A total of 10,883 mosquitoes belonging to three vector species were collected across 20 sites; 6738 were from neighborhood houses, of which 55.4% wereCulex quinquefasciatus, 41.6%Aedes aegypti, and 2.9%Ae. albopictus.Aedes aegyptiwas the most common mosquito resting inside houses (56.7%), whileAe. albopictusandCx. quinquefasciatuswere mostly found resting outside houses (75.7%). In the cemeteries,Cx. quinquefasciatus(60.8%) andAe. albopictus(37.3%) were the most abundant, whileAe. aegypti(1.9%) was the least abundant. This is the first report to identify adults of three major disease vector species coexisting in the domestic environment of urban and semiurban sites andAe. albopictusadult resting inside of urban houses in Mexico. It would be opportune to consider comprehensive strategies that can be applied in this region to control the three species at the same time and avoid outbreaks of the diseases they transmit.