Background:Nearly 10% of women of reproductive age suffer with endometriosis, a chronic inflammatory disorder marked by the presence of tissue resembling the endometrium outside the uterus, such as the ovaries and other pelvic structures. The present study was conducted to assess efficacy and safety of 2 mg and 4 mg Dienogest in endometriosis.Materials & Methods:50 women aged 20-45 years suffering from endometriosiswere divided into 2 groups of 25 each. Group I received 2 mg Dienogest and group II received 4 mg, Dienogest for 24 weeks. Relief of EAPP was assessed using the visual analogue scale (VAS) score and improvement in quality of life (QoL) was measured.Results: The mean age (years) was 27.2 and 27.8, weight (kgs) was 56.4 and 54.3, height (cm) was 148.7 and 149.5, BMI (kg/m2) was 27.2 and 27.9, history of infertility was seen in 9 and 12 and CA125 level (IU/mL) was 91.5 and 96.4 in group I and II respectively. The difference was non- significant (P>0.05). The mean VAS at baseline was 70.4 and 68.5, at 12 weeks was 43.6 and 43.1 and at 24 weeks was 39.7 and 31.6 respectively. Physical health score (QoL) at baseline was 42.7 and 43.8, at 12 weeks was 55.7 and 57.4 and at 24 weeks was 59.2 and 55.1 respectively. The difference was significant (P<0.05). Common adverse events in group I and group II were acne in 2 and 3, decreased libido in 4 and 6, weight gain in 1 and 2 and irregular bleeding in 3 and 5 patients respectively. The difference was significant (P<0.05).Conclusion: The best and most successful dose for treating endometriosis is 2 mgDienogest, /day, as it is more tolerable than the 4 mg dose.