Jealousy is connected with the feeling produced by the individual state of awareness. It may be defined as a specific state of organism that appears as a result of realising the advantage of other people in various spheres, their profits and suffered own losses. When it overreaches some level it becomes obsessive, pathologic, destroys all feelings, leads to conflicts and unpredictable decisions towards a jealousy object and towards oneself. The aim of author's research was to diagnose the phenomenon of jealousy, its intensity, subject and ways of behaviour of those affected with this feeling.