The impact of social processes in working groups becomes a great managerial interest, being given the organizational tendency to direct itself towards team work. To support the performance of group, research in management carried a particular accent on the cognitive aspect of the interpersonal relationships, exploring the way and the cognitive processes of share of ideas and memories. In this domain, the emotional aspect remains under considered. The diffusion of the emotions in a group is, however, an intrinsic characteristic with the existence of a group (Sandelands and Clear St, 1993, p. 445). If the results of an experimental study on 223 managers indicate that the cohesion of group has an influence on the performance of the team, the emotional contagion, as an independent variable, explains it more and in a way much more significant.