In this paper we prove that in a metric measure space (X,d,𝔪) verifying the measure contraction property with parameters K∈ℝ and 1<N<∞, any optimal transference plan between two marginal measures is induced by an optimal map, provided the first marginal is absolutely continuous with respect to 𝔪 and the space itself is essentially non-branching. In particular this shows that there exists a unique transport plan and it is induced by a map.