In laboratory bioassays Steinernema glaseri Steiner, S. riobrave Cabanillas, Poinar & Raulston, Heterorhabditis bacteriophora Poinar, and H. marelatus Liu & Berry, were capable of infecting and killing the bark scorpion, Centruroides exilicauda (Wood). Steinernema feltiae (Filipjev) and S. carpocapsae (Weiser) failed to infect C. exilicauda at 22oC. Steinernema glaseri, H. marelatus and H. bacteriophora caused significant mortality at 22oC, indicating the potential role of these parasitoids as a biocontrol option. Efficacy of S. glaseri and H. bacteriophora was reduced in an assay conducted at 25oC. Only S. glaseri was able to reproduce in the target host. Dissection of scorpions at the end of the experimental periods revealed inactive juvenile S. riobrave, H. marelatus and H. bacteriophora nematodes. Both mermithid and oxyurid nematodes have been documented as nematode parasites of scorpions, but rhabditids have not been reported until now. Field bases studies are warranted to assess the usefulness of entomopathogenic nematodes as biocontrol agents of bark scorpions.