Background: Working with client populations who experience high levels of traumatic stress can result in direct traumatization of staff. This in turn often results in high levels of sick leave, stress leave, employee absenteeism and staff turnover. The extent to which staff stress may be mitigated by the presence of a culture of trauma informed care (TIC) has not previously received attention. This study reports on the extent to which staff report traumatizing experiences as part of their job, related traumatic stress and a causal analysis that suggests the potential impact of a TIC environment on mitigating these difficult emotional experiences.Methods: The study surveyed 321 frontline workers in 27 programs within 19 organizations that provide intervention and support services to persons experiencing homelessness. The survey included the PROQoL, LEC-5 and the PCL-6, and a set or questions on organizational functioning. Statistical analysis included examination of the correlation of traumatic stress, secondary traumatic stress, burnout, and organizational factors of trauma informed care. We conducted a mediation analysis using the framework proposed by Hayes [1] to examine the role of organizational environment on staff traumatic stress. Results: The study affirms the high rates of traumatic experiences and the high rate of stress reported by frontline workers. The mediation analysis establishes model that shows a direct link between trauma-informed organizational practices and reduction in staff reported traumatic stress symptoms.Conclusions: Previous studies have concentrated on secondary traumatic stress. This research highlights that high rates of direct traumatic stress on frontline workers and demonstrates a potential pathway of stress reduction in organizations that have a trauma-informed environment.