A well-known theorem of Paulsen says that if A is a unital operator algebra and ϕ : A → B(H) is a unital completely bounded homomorphism, then ϕ is similar to a completely contractive map ϕ ′ . Motivated by classification problems for Hilbert space contractions, we are interested in making the inverse ϕ ′−1 completely contractive as well whenever the map ϕ has a completely bounded inverse. We show that there exist invertible operators X and Y such that the map XaX −1 → Y ϕ(a)Y −1 is completely contractive and is "almost" isometric on any given finite set of elements from A with non-zero spectrum. Although the map cannot be taken to be completely isometric in general, we show that this can be achieved if A is completely boundedly isomorphic to either a C * -algebra or a uniform algebra. In the case of quotient algebras of H ∞ , we translate these conditions in function theoretic terms and relate them to the classical Carleson condition.2010 Mathematics Subject Classification. Primary:47L30, 46L07, 47L55.