This research explores the importance of the role played by organizational cultures and by leadership management in the prevention of mobbing, referring to the psychosocial reality of work organizations. Although we regard mobbing as the most destructive type of violence in the workplace, the role of leadership in these dynamics is still included in the discussion. This study considers mobbing as the expression of distructive dynamics of relationship, starting from the inspection of interpersonal and social dynamics. Precedent surveys (Trentini G. – Bolla M.C. – Bustreo M. – Trentini A., 2005), studied the organizational circumstances in which habitual conflicts could turn into mobbing dynamics. Mobbing involves the «state of health» aspect of both the internal environment and the leadership management. More specifically, during an escalating conflict, mobbing could develop in the presence of negative dynamics of power environment management. The effect of this situation makes the victims more socio-emotionally and psychologically vulnerable, and thus less able to cope with their daily tasks and the cooperation requirements of their job. The role of leaders seems essential, either in the prevention/control of the phenomenon – positive leadership – or as the inciting element – negative leadership – in their inability to have a relationship with their own group.