Mental health problems have become one of the most common causes of incapacity for work, and engender high costs to society. Especially managerial behavior was found to have a great impact on employees' well-being. In order to support those in leading positions in dealing with their own, as well as their employees', psychological stress factors, we conducted a specific manager training. At the same time, we wanted to find out about the training's short-and long-term effects. Participants were asked to give information about their knowledge and attitudes concerning mental health (Mental Health Knowledge Schedule, Social Distance Scale), as well as to comment on their own health condition (12-Item Short Form Health Survey, Patient Health Questionnaire) and working situation (Effort-Reward Inventory, Irritation Scale). Data were collected at baseline, as well as 3 and 12 months after the training. Results show long-term improvements in knowledge and attitudes measured by the Mental Health Knowledge Schedule (MAKS: M t1 = 22.88, Mt2 = 23.79, Mt3 = 23.79, p = 0.005) but not in the Social Distance Scale (SoDi: M t1 = 0.96, Mt2 = 0.85, Mt3 = 0.84, p = 0.165). Over the period of time observed, no changes were found regarding health-or work-related instruments. Due to the uncontrolled design of the study, further research is needed to determine the exact effectiveness.