The incompressible Navier-Stokes equations characterize a variety of flows, which play an important role in many engineering applications. In this talk, we present a class of Discontinuous Galerkin (DG) methods for solving both the steady-state and time-dependent Navier-Stokes equations. The DG methods offers several advantages, including: (i) flexibility in the design of the meshes and in the construction of trial and test spaces, (ii) local conservation of mass, (iii) h-p adaptivity and (iv) higher order local approximations. In our method, the fluid velocity (resp. pressure) is approximated by discontinuous polynomials of order k (resp. k-1) . We prove an inf-sup condition valid on general nonconforming meshes. In the time-dependent case, we study a particular operator splitting technique that decouples the non-linearity and incompressibility condition. We also consider a subgrid eddy viscosity method for high Reynolds number. A priori error estimates and numerical results are given.