We report a cluster of pediatric diarrhea due to Shigella dysenteriae serotype 1 involving 11 children in France, including the index case, who had returned from Senegal. Child-to-child transmission was documented by ribotyping. Five children developed hemolytic uremic syndrome (HUS). On the basis of our findings, the choice of antimicrobial treatment for infections with S. dysenteriae serotype 1 should take into account widespread drug resistance and the risk of HUS.