Levodopa-induced dyskinesia (LID) is a major limitation of long-term management of Parkinson's disease. The roadblocks that have hindered the development of new treatments for levodopa-induced dyskinesia were discussed at a meeting organized by the Michael J. Fox Foundation for Parkinson's research (New York, NY, March 2011). Among these, the lack of consensus methodology and clinical applicability for eliciting and rating LID in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys was highlighted as a particular concern. Here we present an update on the practical use of rating scales for evaluating LID in MPTP-lesioned primate models of PD, with a focus on macaques, and present specifics on the Non-Human Primate Dyskinesia Rating Scale.