The mapping of chaotic rocks has led to the definition of principles, criteria and methods useful in their differentiation and characterization on the field. Basically field mapping has allowed the distinction of four types of chaotic rocks: 1) argillaceous or shaly-matrix sedimentary breccias; 2) in situ non-metamorphic tectonites or broken/dismembered formations (subdivided in monoformational and multiformational non- metamorphic tectonites); 3) gravity-displaced non-metamorphic tectonites or tectonites in secondary position; and 4) association of sedimentary breccias and tectonites. Specific examples of selected areas from different tectonic settings of the Apennines (southern Abruzzo, Oltrepo Pavese and southern Tuscany) are provided.