Almost nothing is known about atypical kinases in multicellular organisms, including parasites. We have analysed three RIO kinase genes, riok-1, riok-2 and riok-3, and their products from Haemonchus contortus, one of the most important parasitic nematodes of small ruminants. Based on comparative modelling using the known structures of RIOK-1 and RIOK-2 from Archaeoglobus fulgidus [1,2], the structural comparison of the three RIOKs shows that the RIOK domain harbouring the catalytic site is a wellconserved fold among parasitic nematodes, in particular between H. contortus and T. vitrinus. In a first attempt to probe the active site of RIOKs, with a view toward drug discovery, we conducted an in silico screen with the program LIDAEUS using the homology model of Hc-RIOK-1 and employing the SPECS database. Our findings indicate opportunities for the design of a novel class of nematodespecific inhibitors of RIO kinases. The latter aspect is of paramount importance, given the serious problems linked to anthelmintic resistance in parasitic nematode populations of livestock.