In engineering, aerodynamic design of land vehicles, aircrafts and naval vehicles decreases drag coefficients, and as a result of this, the power required is reduced, and thus the fuel consumption is decreased. In a bicycle that runs with only human power, especially in racing bicycle enhancement in aerodynamic perspective, reduces power consumption and thus increases effectiveness. In this study, the aerodynamics of bicycles, parameters effecting aerodynamic design, riding aerodynamics and necessary aerodynamic calculations have been considered, and also conditions required in order to decrease aerodynamic resistance have been examined in detail.