This article is the second in a series reporting on research exploring the effects of Mindfulness-based Stress Reduction on nurses and describes the quantitative data. The third article describes qualitative data. Treatment group participants reduced scores on 2 of 3 subscales of the Maslach Burnout Inventory significantly more than wait-list controls; within-group comparisons for both groups pretreatment and posttreatment revealed similar findings. Changes were maintained as long as 3-month posttreatment. Implications of these findings are discussed.