Female inmates involved in the Yoga Prison Project at two correctional facilities in South Carolina served as subjects. Inmates were selected from those who applied to participate in a ten-week trauma-focused yoga program. To create control and experimental groups, inmates who requested to participate were randomly assigned to be in the class (Treatment Group, n = 33) or a waitlist (Control Group, n = 17). Inmates on the waitlist subsequently joined the next class, so all who applied and were eligible participated in a yoga class. Measures of stress, depression, self control, anxiety, self awareness and rumination were used and data was collected from both groups before the initial yoga class began and again at the end, ten weeks later. To assess the changes from pre-intervention to post-intervention, mixed design ANOVA tests were conducted. Inmates in the yoga group reported significant decreases in depression and stress and improved self-awareness. No significant changes were found on measures of anxiety, rumination and self-control in the yoga groups. Although not statistically significant, anxiety scores did decrease and self-control scores improved for the yoga group, while inmates in the control group reported a worsening or no change on these two measures. No changes were found in rumination levels. The results suggest that Yoga is a relatively inexpensive intervention that could benefit both inmates and prison staff by reducing some negative behaviors and possibly mental health problems.