OBJECTIVES: To evaluates and compares the cost effectiveness of 2mg dienogest versus gonadotropin-releasing hormone analogs (GnRH-a) for endometriosis treatment. Some treatments only eliminate endometriosis symptoms while others shrink and reduce lesions in addition to symptom treatment. In this context, dienogest was compared to the class of GnRH analogs, which are used in Turkey for both symptomatic treatment and as a contributor to shrinkage/reduction of the endometriotic lesions. METHODS: The population consisted of women age 18 to 49 eligible for GnRH-a treatment. GnRH-a treatment included leuprolide acetate (3 months intramuscular / subcutaneous injection 11.25mg, 1 syringe/box) and goserelin acetate implant (3.6 mg 1 syringe/box). A Markov model was used to simulate  three health outcomes: treatment response, unresponsive to treatment and death. Costs were assessed and compared between the 2mg dienogest group versus the selected GnRH-a group over a 2-year time period. Clinical endpoints were quality adjusted life years (QALY) and mean response time (≥50% improvement in Visual Analog Scale[VAS] pain score) in health status when a patient responded to treatment.  Model output was calculated as incremental cost per QALY and per respondent years gained. RESULTS: A 2-year model was utilized for GnRH-a therapy and supporting treatment, and a 1-year model for treatment without supportive therapy. Study results showed that dienogest had the same efficiency but lower healthcare costs according to incremental cost per QALY and per respondent years gained for both the 1 and 2-year models. Sensitivity analysis for treatment response and regression rate also showed that 2mg dienogest was a more cost-effective treatment option than GnRH-a agents. CONCLUSIONS: Results demonstrate that 2mg dienogest is a more cost-effective option to treat endometriosis compared with both GnRH-a agents. This result may assist with reimbursement plan selection for endometriosis treatment from payers’ perspectives.