Heat transfer characteristics during forced convective condensation of a vapor inside a smooth horizontal tube under annular flow pattern is numerically studied. For the purpose of this study, using the Volume of Fluid (VOF) method simulates a turbulent two-phase flow inside a round tube. The results are compared with experimental data presented by Dobson , Chitti  and available correlations of other investigators. The comparison shows good agreement with the experimental data. The maximum deviation of mean Nusselt number calculated by this procedure compared with the experimental results is 8 percent.