We report the case of an elderly patient with cobalamin deficiency who progressively developed cognitive and behavioral symptoms associated with neuropsychiatric disturbances. His neuropsychological profile showed many features suggestive for a frontal-dysexecutive syndrome and was related to a predominant asymmetric (right > left) frontal lobe hypoperfusion. He completely recovered after a treatment with vitamin B12 and follow-up of 7 years showed that his improvement remained stable. Along with the other cases reported in the literature, our case also proves that there are some cases of vitamin B12 deficiency that can manifest with the symptoms of frontotemporal dementia and that they are completely reversible after substitution therapy.