In this paper, we compute competition indices and periods of multipartite tournaments. We first show that the competition period of an acyclic digraph D is one and ζ(D) + 1 is a sharp upper bound of the competition index of D where ζ(D) is the sink elimination index of D. Then we prove that, especially, for an acyclic k-partite tournament D, the competition index of D is ζ(D) or ζ(D) + 1 for an integer k ≥ 3. By developing useful tools to create infinitely many directed walks in a certain regular pattern from given directed walks, we show that the competition period of a multipartite tournament with sinks and directed cycles is at most three. We also prove that the competition index of a primitive digraph does not exceed its exponent.