Capgras and Fregoli syndromes are two psychotic and complex conditions also known as Delusional Misidentification Syndromes (DMSs). Their description dates back to the beginning of XX century, and many explanatory models have been formulated through myths, psychoanalytical and psychological hypotheses, as well as neurobiological proposals. Even if DMSs are not fully considered in the modern diagnostic manuals, they still remain intriguing phenomena to be clinically observed and explained. Also, the employment of psychotropics and physical techniques in the treatment of such conditions is not supported by robust evidences and this may encourage further studies. We conclude that it would be of great interest to brush up the neglected MDSs in order to improve our knowledge on the underlying mechanisms of delusion and brain functioning.