CoRe (CognitiveRehabilitation) is a system for the automatic generation of patients-personalized exercises based on an ontology of stimuli (words, images and sounds). The system is characterized by the following main components: (1) a stimuli ontology characterized by almost 6000 concepts organized in taxonomies, described by attributes and connected to one another through relationships; (2) a database to store performance data monitored during rehabilitation therapy, as well as personal information like hobbies, family member names, preferences (sports, colors, animals, etc) that are fundamental for the exercise customization; (3) a database, created starting from the ontology, to store the available stimuli and make them work properly with other system components; it also contains all the parameters needed for the automatic modulation of difficulty; (4) a repository with the formal descriptions of the exercises and the modalities for modulating the difficulty; (5) the back end: a software engine for the dynamic generation of the exercises based on their formal description and the parameters selected by the therapist; (6) the front-end: a graphical interface that allows the therapist to set the parameters required for the execution and the dynamic generation of the exercises.