Dengue fever is a vector-borne viral disease which is now endemic in more than 100 countries affecting more than 2.5 billion people worldwide. In recent years, dengue fever has become a major threat to public health in Pakistan. In this paper, we derived an explicit formula for reproduction number R0 (the most important epidemiological parameter) and then used real data of dengue fever cases of different hospitals of Lahore (Pakistan) on R0. Conditions for local stability of equilibrium points are discussed. In the end, simulations are carried out for different situations.