In this study, 2654 adults and mosquito larvae, which belong to 18 species and 4 genera, were collected: Aedes (2 spp.), Anopheles (7 spp.), Culex (8 spp.) and Culiseta (1 sp.). They were Aedes caspius, Ae. aegypti, Anopheles. azaniae, An. d'thali, An. multicolor, An. rhodesiensis, An. stephensi, An. Sub-pictus, An. turkhudi, Culex laticinctus, Cx. perexiguus, Cx. pipiens, Cx. quin-quefasciatus, Cx. simpsoni, Cx. theileri, Cx. tritaeniorhynchus, Cx. univittatus and Culiseta longiareolata. A total of 2270 mosquito larvae were collected, and Culex spp. were the most abundant, where 1629 (71.76%) larvae were collected, followed by 499 (21.98%) Anopheles spp., 94 (4.14%) Aedes spp. and 48 (2.12%) Culiseta longiareolata. Of, 384 adult mosquitoes collected Culex spp. were the most abundant and 328 (85.42%) were collected, followed by 22 (5.73%) Aedes spp., 19 (4.94%) Anopheles spp. and 15 (3.91%) Culiseta longiareolata. The physical properties of the water in the breeding sites of mosquito larvae showed that pH of water varied between 6.9 & 9.9, the total dissolved salts (TDS) varied between 378-9504 ppm and water temperature varied between 8.7 degrees C in winter to 29.9 degrees C in summer. There was no correlation between pH & TDS of water in breeding site and distribution of larvae. The population density started to increase in March, with a peak in August when temperature was 36 degress C. The activity started to decrease in October, and minimum activity was in January, when temperature was below 5 degrees C. The seasonal abundance of adult mosquitoes was not affected by rainfall. A. aegypti, vector of Dengue fever virus, Cx. tritaeniorhynchus, vector of Rift Valley fever and Cx. univittatus, vector of sindbis virus were reported for the first time in Al Madinah Al Munawwrah Region. These vectors constituted a major health problem, and every effort should be made for feasible control.