The technique named mechanical alloying has been historically used for designating many different process routes, in spite of involving various kinds of materials and purposes. The aim of this work is to make a review of this technique, with special emphasis on the differences between those routes. Based on that, a suggestion for the classification of the various routes is presented. The high-energy ball mill processing can be divided in three main groups according to the mechanisms involved and/or the purpose envisaged: Mechanophysical conditioning, Mechanochemical synthesis and mix processes. In the first group, dissimilar or similar materials can be processed. In the second group, the materials can be synthesized with or without bonding changes during the process. The third one is a combination of the two first processes. Some examples are also presented.