Generally, the spouses, children and relatives of the individuals with Post Traumatic Stress Disorder (PTSD) gradually show symptoms, called Secondary Traumatic Stress Disorder (S.T.S.D). The purpose of the present study was to investigate the effectiveness of training mindfulness based cognitive strategies in the reduction of the symptoms of secondary traumatic stress disorder (S.T.S.D) and psychological problems of the spouses of individuals with Post Traumatic Stress Disorder (PTSD). Therefore, in a semi-experimental design, involving a pre-test and post-test with control group, 28 spouses of individuals with PTSD were selected by using available sampling method and were randomly assigned into experimental and control groups. The experimental group received eight 150-minute training sessions concerning mindfulness-based cognitive strategies. Then both groups were assessed in terms of S.T.S.D, depression, anxiety, dysfunctional attitude, and negative automatic thoughts. The results of the study indicated that mindfulness-based cognitive strategies was effective in the reduction of the symptoms of S.T.S.D and other related variables including intrusive thoughts and notions, depression, anxiety, dysfunctional attitude, and negative automatic thoughts of individuals with PTSD.