Dementia is an increasingly prevalent disease of the ageing population. Although Alzheimer's disease is still the most common cause of dementia, there is emerging clinical interest in other, less common, causes of dementia that can affect patients at a younger age. Early diagnosis of these non-Alzheimer's disease dementias is now possible with the aid of neuroimaging, including computed tomography and magnetic resonance imaging, as well as newer modalities such as magnetic resonance spectroscopy, diffusion tensor imaging, and single-photon emission computed tomography. The imaging features of some of the more common non-Alzheimer's disease dementias will be discussed in this review in order to help clinicians and radiologists better diagnose these conditions.