Due to international trade, tourism, and climate/ecological changes, mosquito species are transported, or disperse, get introduced and eventually become established in new territories. Since August 2017, a nationwide three year monitoring project started in Belgium (MEMO: Monitoring of Exotic Mosquitoes). The project is funded by the Belgian federal authorities and the federated entities, and aims at detecting and evaluating the occurrence of exotic mosquito species (EMS) in Belgium. Monitoring activities started at 23 points of entry (PoE) using adult trapping, as well as egg and larval sampling. Whenever potential EMS are suspected based on morphological identifications, samples are identified using DNA-based techniques as molecular confirmation. Additionally, 5% of the overall annual yield (e.g., about 300 specimens out of approximatively 6,000 in 2017) is also identified using DNA-based techniques to verify morphological identifications as a quality control measure. Fifteen native species (or complexes) of five genera were identified and confirmed by DNA-data. Additionally, all intercepted EMS could be distinguished from the native Culicidae. Presently, four EMS were collected once or multiple times at one or multiple PoEs: Aedes koreicus; Aedes japonicus; Aedes albopictus; and Anopheles pharoensis. In 2018, Aedes albopictus was intercepted at five PoEs, at three of which for the first time. EMS seem to enter Belgium effectively through different introduction pathways: via lucky bamboo and tyre transport, ground traffic, but also possibly by natural dispersal. In this perspective, MEMO will contribute to a better understanding of the introduction process of the different exotic species by providing information on their status (introduction, establishment or spread) and seasonality.