In the quest to translate basic research to the bedside, our capacity to identify and mechanistically define molecular targets for therapeutic intervention is enhanced by the application of animal models that afford opportunities for rapid discovery. Here we describe the salient attributes of the nematode roundworm, Caenorhabditis elegans, as an in vivo system for investigation of mechanisms underlying movement disorders. In the context of arguably the most well-defined metazoan species on Earth, a plethora of modern genomic and genetic tools converge with in-depth and increasingly mature database information to provide a uniquely powerful set of resources poised for experimental exploitation. This chapter outlines a collection of bioassays and methods established to evaluate genetic, environmental, and drug modifiers of key gene products associated with dystonia and Parkinson disease. Moreover, the predictive potential of nematode models is highlighted through representative studies illuminating the utility of C. elegans for movement disorders research.