Objectives: To evaluate the usefulness of combined oral contraceptives (ethinyl estradiol and levonorgestrel) in resolving menstrual pattern disorder in reproductive-age women with a functional ovarian cyst in Iraq. Method: A longitudinal (before and after) , interventional study was used. Data were collected at a single obstetrics and gynaecology outpatient clinic in Mosul City, Iraq. Participants: A sample of 96 women aged between 15 and 45 years participated in the study. Participants diagnosed with ovarian cysts were treated using an oral administration of contraceptive pills (combination of ethinyl estradiol, 0.03 mg, and levonorgestrel, 0.15 mg) on a daily basis for a treatment duration of 2 months. The Outcome Measures are Menstrual pattern disorders (dysmenorrhea, irregular menstrual cycle, and amenorrhea) and cyst dimensions were recorded. Results: After one therapy cycle, a statistically significant disappearance of menstrual pattern disorder was observed (p=0.000). Cyst resolution was observed in 89.58% of the patients (n=86), while mean ovarian cyst size fell from 4.452 ± 1.0603 cm at the start of therapy to 0 .451 ± 1.5613 cm(p = 0.000). 5 of the 10 persistent cysts disappeared after the second cycle (2 months after the start of therapy) and complete cyst resolution was 94.8% (n = 91) after two cycles. This indicated a further significant reduction of mean ovarian cyst size to 0.335 ± 1.4684 cm. However, no significant difference was observed between mean cyst size in the first and second months of treatment (p=0.329). Conclusion: Combined oral contraceptives (ethinyl estradiol and levonorgestrel pills) are effective in relieving dysmenorrhea, irregular menstrual cycle, and amenorrhea. They also hasten the disappearance of functional ovarian cysts, and are associated with high rates of success in patients with functional ovarian cysts.