Complicated grief treatment (CGT) is a new psychotherapy for complicated grief disorder combining strategies from interpersonal therapy, cognitive-behavioral therapy, self- compassion training and motivational interviewing. The aim of the present study was to examine the effectivness of complicated grief treatment on complicated grief symptoms in patients with complicated grief disorder (CGD). This research was administrated in a multiple baseline single subject design framework. Four patients (female, ages 20-42) with CGD were selected through available sampling. To collect data inventory of Prigerson and Jacobs (ICG-R) was administered during baseline, during treatment at sessions 4, 8 and 12, and at 2-month follow-up. The visual inspection of charts and descriptive statistics index indicated significant decrease in complicated grief symptoms of participants. These preliminary findings provided support for the role of CGT in reducing complicated grief symptoms in Patients with CGD.