The author describes an 'attack' of racial prejudice occurring during psycho-analytical treatment. A new concept is introduced—'incorprojection'—to describe the mechanisms underlying prejudice. As the accusations of the prejudices are simply projections of their own traits, it follows that it is they who have feelings of inferiority and of envy. This suggests that those who are free from inferiority and from envy cannot be prejudiced. It is of interest here that prejudice is most common amongst those people who can be described as middle. The author points out that however reprehensible prejudice may be, it is nevertheless an ego defence directed against aggressive impulses. Prejudice implies not only the presence of dangerous id impulses but also the activity of a punitive superego. Prejudice is self-criticism gone wrong.