Social cognitive processes enable to value and respond to social stimuli, and influence interpersonal behaviour and social conduct. Social cognitive processes rely on complex neural networks, now better evidenced by functional neuroimaging techniques. What happens to these social cognitive processes when brain is damaged by a progressive and sometimes fast neurodegenerative disease? This review takes in exam first studies that assessed the processes of social cognition (i.e. Theory of Mind, perspective taking, emotion recognition, empathy, moral judgements) in Alzheimer's Disease, Frontotemporal Dementia, Parkinson's Disease and Huntington's Disease. Findings show that different neurodegenerative diseases cause different patterns of social cognition deficits; Frontotemporal Dementia, especially in its frontal variant, is the clinical disease that presents the most marked impairment of social cognition, a phenomenon that explains the severe disturbances of interpersonal behaviour and social conduct of patients with this disease.