Despite the importance of a brother in the constitution of the subject and social bond formation, only around the year 2000 contemporary authors began to show a greater interest in studying fraternal relationships. However, a great number of these studies and research are dedicated towards competition and rivalry rather than good coexistence and solidarity. In our psychoanalytic based theoretical review, we studied classical authors – Freud, Klein and Adler – and proceeded with contemporary scholars, studying the fraternal relationship in its dispute and rivalry aspects, as well as in its solidarity and companionship elements. We focused the formation of the phratry, the position in the phratry, the fraternal bond, the fraternal complex and the social bond. We verified the importance of the phratry in the constitution of the subject and of the social bond. We illustrate the theoretical discussion with fragments of clinical cases.