AbstractDuring the last decades, atypical parkinsonian disorders such as multiple system atrophy, dementia with Lewy bodies, progressive supranuclear palsy, and corticobasal degeneration along with secondary parkinsonian disorders have been increasingly recognized as important causes of parkinsonism. Although treatment options are largely limited to date, remarkable progress has occurred through advances in the fields of molecular biology and diagnostic neuroimaging, resulting in intense preclinical drug discovery programs. Early‐investigation‐assisted clinical diagnosis has become more crucial than ever because disease‐modifying therapies will hopefully become available within this decade. © 2011 Movement Disorder Society