The neuropsychological follow-up study of a 58-year-old man suffering from Motor Neuron Disease (ALS/MND) and Fronto-Temporal Dementia (FTD) is reported. Neuromuscular signs first appeared at the age of 51 and slowly progressed to late bulbar involvement; behavioural symptoms of the frontal type first appeared around age 53; lastly, several neuropsychological symptoms suggestive of worsening temporal involvement supervened at age 57. Our patient died at 59 of respiratory failure with the classic clinical and neuroradiological picture of FTD. A short discussion addresses the controversial issue of the coupling of ALS/MND with Dementia and its possible interpretation as the expression of a chance association of relatively common diseases, versus that of a single multifaceted disease. The role of a detailed neuropsychological assessment is highlighted, within the context of increasingly specific diagnostic criteria for FTD.