Advantageous features that makes C. elegans a suitable model organism to study human neurodegenerative diseases includes its body transparency for direct visualization of neurons, a reproductive cycle of three days, a life span of three weeks, and richness in posture, movement, and behavior. C. elegans has well-developed methods and resources for genetic manipulation, including visible phenotypic markers, a completed genome sequence, a library of mutants, and the ability to perform forward and reverse genetics. Parkinson's disease models produced from the wild-type C. elegans can be divided into classes based on genetic mutations, chemical treatments, and transgenic manipulations. The models recapitulate some features of human Parkinson's disease that can be seen at the biochemical, cellular, and behavioral levels. A recent report that compared gene expression patterns during aging in C. elegans and Drosophila models indicates the feasibility of such an approach. More human genes involved in familial Parkinson's disease could also be constructed as a C. elegans model, either by over expression or mutation. Parkinson's disease immediately comes to mind as a viable candidate. The use of models, such as C. elegans, provides new ideas and concepts at a rate that is faster, cheaper, and more ethically acceptable than models in higher organisms. © 2005 Elsevier Inc. All rights reserved.