Background: It is well known that mosquito species transmitted diseases such as: filariasis, malaria fever and allergy to humans. Materials and Methods: Collected mosquito species adults were identified morphologically using recommended keys constructed by specialized authors. Also, different climatic factors (temperature, relative humidity, and wind velocity), of adult mosquitos' habitats were measured, and the relationship between climatic factors and adult mosquitos' abundance were investigated.  Results:The obtained results revealed that mosquito species in Beheira Governorate, Egypt, were represented by four genera and nine species these are:  Culex pipiens, Cx. antennatus, Cx. theileri, Cx. tritaeniorhynchus, Culiseta longiareolata, Aedes caspius, Ae. detritus, Anopheles multicolor and An. sergentii. Based on statistical analyses, the abundance of adult mosquitoes had a moderately positive correlation at all species collected with temperature except Ae. detritus has a weak positive correlation. At the same time, relative humidity recorded a moderately negative correlation for all species studied except Ae. detritus which did not show correlation. In addition, wind velocity was negatively correlated at all species except Ae. detritus recorded weak positive correlation. Conclusion: The most abundant mosquito species in the studied areas were Culex pipiens which have been collected throughout different seasons, which threatens the risk of spreading diseases transmitted by this species. Also, the abundance of mosquito species proved to depend on suitable climatic factors. So, more investigations are needed to select a proper control strategy.