In this paper we investigate
unitary equivalence of invariant subspaces of the Bergman and the Dirichlet space.
By definition, this means unitary equivalence of the multiplication operator Mz
restricted to the invariant subspaces.
We show that no two invariant subspaces of the Bergman space are unitarily
equivalent to one another unless they are equal. Under some extra assumption
on the invariant subspaces we obtain a similar result for the Dirichlet
space.