Objective: Endometriosis is a common disease that affects 5%-15% of women of reproductive age. This study aimed to evaluate the effect ofdienogest (DNG) on improving pain scores of patients with endometriosis.Methods: Data of 77 women who were admitted to the endometriosis clinic from March 1, 2015, to March 1, 2017, were evaluated. Patientswere divided into 2 groups: DNG group (n=46) or group that denied use of any medication (expectant management group, n=31). The mainpresenting symptoms were graded using the visual analog scale (VAS). Age, parity, gravidity, body mass index (BMI), VAS scores, and furthersurgery requirement of the study groups were compared.Results: The most common presenting symptom was dysmenorrhea (79.2%), and the least common was dysuria (7.8%). No statisticallysignificant difference was found between the study groups in terms of age, parity, gravidity, BMI, and further surgery requirement. A significantdifference was found in the reduction of dysmenorrhea, dyspareunia, dyschezia, and pelvic pain VAS scores between the study groups, andmore reduction was observed in the DNG group after 6 months of follow-up (p<0.001, p=0.04, p=0.009, and p=0.01, respectively).Conclusion: DNG might be an alternative treatment for reducing pain symptoms related to endometriosis.