Yannakakis and Gavril showed in  that the problem of finding a maximal matching of minimum size (MMM for short), also called Minimum Edge Dominating Set, is NP-hard in bipartite graphs of maximum degree 3 or planar graphs of maximum degree 3. Horton and Kilakos extended this result to planar bipartite graphs and planar cubic graphs . Here, we extend the result of Yannakakis and Gavril in  by showing that MMM is NP-hard in the class of
-regular bipartite graphs for all
≥ 3 fixed.