A (finite) partial order P is monomorphic if for all v, w ∈ V (P ), Pv ≃ P -w. Moreover, a partial order P is bimorphic if there exist x, y ∈ V (P ) such that Px ≃ Py, and for every v ∈ V (P ), we have Pv ≃ Px or Pv ≃ Py. Using the modular decomposition, we characterize the monomorphic partial orders and the bimorphic partial orders. Their reconstruction follows from these characterizations.