Mutations in the gene for leucine-rich repeat kinase 2 (LRRK2) have been linked to several familial and sporadic late-onset cases of Parkinson's disease. The cumulative data for the effects of mutant forms of this enzyme on neuronal degradation and the pathophysiology of Parkinson's disease create a compelling case for drug discovery based on inhibition of the mutant forms of LRRK2. This review focuses on structure-activity relationships for inhibitors of LRRK2 and the data supporting a potential role of these agents in treating Parkinson's disease.