The prevalence of mental health and addiction issues in the homeless population is very high. Mindfulness based interventions have been shown to have positive impacts on anxiety, depression and addiction in various populations. Mixed methods explored the impact of a mindfulness based stress reduction (MBSR) intervention for 12 homeless men. Quantitative measures of anxiety, depression, impulsivity and emotional reactivity were completed pre and post intervention, and participants were interviewed about their experiences of MBSR. Statistically significant changes in anxiety, depression, emotional reactivity and impulsivity were found. The qualitative data highlighted how mindfulness skills can easily be taught to this population, and through the use of these skills, participants were able to develop enhanced coping skills, mindful traits, well-being and an improved capacity to deal with their mental health and addiction issues. This study gives support to the promising potential of mindfulness interventions being implemented by mental health care professionals with homeless service users.