We examine different topological phases in three-dimensional non-centrosymmetric superconductors with time-reversal symmetry by using various topological invariants. Due to the bulk boundary correspondence, a non-zero value of these topological numbers indicates the appearance of zero-energy Andreev surface states. In fully gapped phases the presence of these surface states is independent of the surface orientation, whereas in nodal superconducting phases the Andreev states appear only for certain orientations of the surface. These Andreev surface bound states have many observable consequences: In particular they lead to a zero-bias conductance peak in the scanning tunneling spectra.