This Master Thesis is focused on the estimation the hydrodynamic coefficients for Underwater Autonomous Vehicle (AUV) by means of CFD code. First a state of art of AUVs development is presented. Second, the sizing process for AUVs is studied. The main decissions on the design of this type of vehicles is showed. Third, hydrodynamic coeffcients required to solid rigid movement of AUV is presented. Fourth, an estimation of these coefficient is carried out using different formulation. Fifth, coefficient for REMUS 100 AUV are estimated using CFD code Tdyn. Then a comparison with experimental results obtained for others authors is showed. Finllay, some interesting conclusions and futher reseach are outlined.