The most common reason for sick leave in Sweden today is mental illness (Försäkringskassan, 2015) and this is a problem both at the individual level and the community level (Socialförsäkringsrapport, 2014: 4). The purpose of this paper is to understand how the Human Resource professionals (HR professionals) in Swedish companies define, identify and manage mental illness in the workplace and the effect of leadership, organizational culture and bureaucracy, and how it affects their power. The result is from qualitative interviews with six HR professionals at Swedish companies. A definition of mental illness from an HR perspective is that mental illness can be divided into two parts, stress-related symptoms but also victimization and being badly treated by colleagues. They identify mental illness by being aware of anxiety, bad mood, acting out, and if someone gets hardcover. They discover it also through good communication, both through everyday conversation as well as performance review, and by keeping track of the hours spent in the workplace. The management of mental illness most often occurs through cooperation with other organizations and various interventions are successful for different people, which make the managing difficult. In the managing of employers, the HR professionals can make certain demands on collaboration, just as the worker can set certain requirements. How the HR professionals define, identify and manage mental health of their employees is affected by the leadership, organizational culture and bureaucracy, and that in turn affects how power is being used in that relationship.