Dengue is currently the most widespread vector-borne disease, and its transmission has been intensively studied in endemic/hyperendemic localities. However, to obtain a complete picture of dengue transmission, it is necessary to study nonendemic localities. Imported dengue cases have been reported in Mexico City, and the presence of eggs of the vector Aedes aegypti has been detected. In the present study, we determined the prevalence of IgG antibodies against Dengue virus in four city boroughs via random cluster sampling in individuals aged 5-35 years. The weighted seroprevalence rate was 1.90% (95% CI 0.75-4.75) at Xochimilco, 1.81% (95% CI 0.64-5.00) at Venustiano Carranza, 1.81% (95% CI 0.54-5.83) at Tlahuac, and 5.48% (95% CI 1.96-14.43) at Gustavo A Madero; seropositivity was concentrated in the adult group, many of whom lived in dengue-endemic localities. The distribution of seroprevalence in the four boroughs is very homogeneous and unrelated to the number of vector eggs in the borough. These data suggest that there is still no autochthonous transmission of dengue in Mexico City. However, it is important to note that the structural conditions of the dwellings in these boroughs, which offer minimal barriers to vector infestation, could facilitate the establishment of local transmission under favorable conditions.