The biogenic amines, serotonin, octopamine, tyramine and dopamine regulate many essential processes in parasitic nematodes, such as pharyngeal pumping, muscle contraction, and egg-laying, as well as more complex behaviors, such as mechanosensation and foraging, making biogenic amine receptors excellent targets for drug discovery. This review is designed to summarize our knowledge of nematode biogenic amine signaling and preliminarily identify some of the key receptors involved in the regulation of biogenic amine-dependent behaviors through an analysis of the free-living nematode, Caenorhabditis elegans.