The residual ovary syndrome (ROS) occurs in patients where one or both ovaries are conserved at the time of hysterectomy. It occurs mostly within 10 years of hysterectomy. Residual ovary syndrome usually requires surgery and histology varies from some physiological cysts to benign or even malignant neoplasms. The objectives of the study were to analyze the etiopathology of re-operation for ROS and to find out their clinical presentations. This cross-sectional observational study was conducted in the department of Obstetrics and Gynaecology, BSMMU during a period of 5 years from January 2014 to December 2018. All consecutive patients admitted with residual ovary syndrome (ROS) at the department of Obstetrics and Gynaecology and also in Gynae-oncology department at Bangabandhu Sheikh Mujib Medical University (BSMMU), Bangladesh. Total 40 cases were enrolled according to selection criteria and sampling technique was purposive. The mean age of the study populations was 42.20±7.13 years. All of the study populations were parous except one who was nulliparous. The mean age of hysterectomy was 37.25±6.44 years. The indication of primary surgery by hysterectomy was fibroid in 50% of cases; others were abnormal uterine bleeding, pelvic inflammatory disease etc. After primary surgery majority (77.5%) of the study populations presented with chronic pain with or without dyspareunia and 20% presented with lump in abdomen either symptomatic or asymptomatic. Around half (57.5%) of the patients were presented within 5 years and 82.5% within 10 years of hysterectomy. Per-operative findings of secondary surgery for ROS were mainly extensive peri-ovarian and peritoneal adhesions involving surrounding structures. Among them majority (77.5%) of the cases were presented with various types of cystic and complex masses in the ovaries. Histopathological reports of residual ovary were functional cysts 35.0% (n=14), Corpus luteal cyst 12.5% (n=5), endometriotic cyst 12.5% (n=5), benign ovarian tumours 37.5% (n=15) and malignant ovarian tumour 2.5% (n=1). ROS, usually requires surgery which in most of the cases becomes troublesome due to presence of extensive adhesions with surrounding structures. So, decision is crucial whether to remove or conserve apparently healthy ovaries found at hysterectomy in pre-menopausal women. Moreover decision of hysterectomy in premenopausal women should be taken very judiciously as several medicines are available for conservative management. Usually indications of hysterectomy are benign.