Smell dysfunction is among the earliest and most salient non-motor signs of Parkinson’s disease (PD), occurring in an estimated 90% of so-called sporadic cases years before the onset of the classic motor symptoms. Until olfaction is tested formally, the vast majority of PD patients are unaware of their loss, which is usually less than total. The smell problem is rarely identified by neurologists, reflecting, in part, their failure to enquire about smell function let alone testing the olfactory nerve formally. The Quality Standards Committee of the American Academy of Neurology has designated olfactory dysfunction as one of the key diagnostic criteria for PD [1] and the Movement Disorder Society has recommended olfactory testing in the diagnosis of PD [2] and in the identification of prodromal PD [3].