In spite of the great technological progress achieved worldwide, still arthropod borne infectious diseases is a puzzle disturbing the health authorities. Among these arthropods, mosquitoes from medical, veterinary and economic point of view top all groups. They are estimated to transmit disease to more than 700 million people annually worldwide mainly in Africa, South America, Central America, Mexico and much of Asia with millions of deaths. In Europe, Russia, Greenland, Canada, the United States, Australia, New Zealand, Japan and other temperate and developed countries, mosquito bites are now mostly an irritating nuisance; but still cause some deaths each year. Mosquito-borne diseases include Malaria, West Nile Virus, Elephantiasis, Rift Valley Fever, Dengue Fever, Yellow Fever and Dog Heartworm…. etc. Apart from diseases transmission, mosquitoes can make human life miserable. The successful long term mosquito control requires the ecological and biological knowledge of where and how they develop. The importance of mosquitoes is given herein to clarify the problem and to think together what one must do?