In the present research study, an analysis is made of aggression between inmates as an excessive and informal punishment, for those who enter the prison to wait for a criminal process or to serve a sentence, respond to violence with their own violence due to distrust in the coherence of the internal structures of the agents of social control and in the rejection of those who subject them to it. The conditions that facilitate aggression between inmates are identified through the definition of the mechanisms that justify it, examining the responsibilities of those responsible for the exercise of authority and the effects under which aggressive behaviour between inmates is translated; through the explanation and description of facts taken from the behaviour assumed by the inmates in order to analyse a reality that goes unnoticed by the entities involved.