A large proportion of human social neuroscience research has focused on the issue of decision-making. Impaired decision-making is a symptomatic feature of a number of neurodegenerative diseases, but the nature of these decision-making deficits depends on the particular disease. Thus, examining the qualitative differences in decision-making impairments associated with different neurodegenerative diseases could provide valuable information regarding the underlying neural basis of decision-making. Nevertheless, few comparative reports of decision-making across patient groups exist. In this Review, we examine the neuroanatomical substrates of decision-making in relation to the neuropathological changes that occur in Alzheimer disease, frontotemporal dementia, Parkinson disease and Huntington disease. We then examine the main findings from studies of decision-making in these neurodegenerative diseases. Finally, we suggest a number of recommendations that future studies could adopt to aid our understanding of decision-making cognition.