This chapter deals with the 'other' causes of parkinsonism with the ex
clusion of idiopathic Parkinson's disease, multiple system atrophy, pr
ogressive supranuclear palsy and corticobasal degeneration. It is a cu
rsory glance over the endless list of 'secondary' causes of parkinsoni
sm or parkinsonism due to acquired and inherited metabolic and neurode
generative diseases. With the exception of drug-induced parkinsonism a
nd 'vascular' parkinsonism, most such cases are rare. However, single
rare causes must not be overlooked as there can be specific therapeuti
c consequences. Parkinsonism is often present amid a constellation of
other symptoms. Careful evaluation of the personal, familial and envir
onmental context, mode of onset and progression, clinical features, an
d drug response, together with imaging, biochemical and molecular test
s, help in determining the underlying disease.