Mednykh's formula provides a way of counting the number of homomorphisms between the fundamental group of a closed orientable surface M and any finite group G, in terms of the Euler characteristic of M and the dimensions of the irreducible representations of G. In this talk, we will prove Mednykh's formula by constructing an appropriate 2d-TQFT (untwisted Dijkgraaf-Witten theory) and computing the topological invariant assigned to M in two different ways.