The control of parasitic nematode infections in humans, livestock and companion animals is critically dependent on anthelmintic treatments. However, the indiscriminate use of anthelmintic drugs has inevitably led to the selection of resistant parasites. In this context, diagnosis tools are of particular interest to monitor the resistance spreading and refine strategies for the control of resistant parasites. In this presentation, recent advances in automated phenotypic assays performed on larval stages of the parasite will be discussed. In addition, based on the example of the imidazothiazoles/tetrahydropyrimidines anthelmintics, the identification and functional validation of molecular markers associated with resistance will be presented, opening a discussion about the advantages and limitations of the use of C. elegans as a model for parasitic species.