Purpose of Investigation: Adnexal masses identified on imaging are often designated rightor left-sided, but findings at surgery can be different from what was described preoperatively. The objective was to assess laterality concordance between preoperative imaging modalities and operative findings/final surgical pathology. Secondary outcomes included analysis of: mass size, patient age, histological diagnosis, and imaging modality on delineation of adnexal mass sidedness. Materials and Methods: This was a retrospective chart review from a single sub-specialty provider and 705 patients were reviewed from January 2015 through October 2017. There were 280 patients with an admission diagnosis of pelvic Mass included in the final analysis. All patients had some form of preoperative imaging consisting of either: CT, ultrasound, or MRI. Results: Concordance between imaging and surgical findings was poor at 35.9%. Concordance between imaging modalities themselves was 30.3% for CT and ultrasound, and 50% for MRI and ultrasound. The authors found that the larger the mass size, the lower the sensitivity for correctly assessing laterality (47.62% for size < 7 cm vs. 18.75% for size ≥ 20 cm, p = 0.0378). Age had some effect on mass size with those ≤ 30-years-old having significantly larger masses p = 0.0167. For those with ovarian type cancers, there was a significant difference between mass size and age ≤ 30-years compared to > 30-years-old (p = 0.046). A benign versus cancer diagnosis did not increase the ability to discern sidedness (Fishers test p = 0.3110). The size discrepancy between preoperative imaging and final pathology ranged from 0-14.9 cm with an average of 2.45 cm. Of the 72 women with high grade serous tubo-ovarian cancer (HGSTOC), 34.7% were found to not have specific “adnexal” masses, but other pelvic mass findings were identified. Conclusions: Preoperative imaging does not confer significant concordance of laterality with surgical findings in any patient subset. This can become an issue with consent forms and compliance with national and local administrative guidelines regarding wrong-side, wrong-site surgeries. Counseling for patients can be inclusive and stated as such on the consent forms. A high suspicion for HGSTOC should be held when a perior postmenopausal patient presents with abdominal/pelvic symptoms and no adnexal mass specifically identified.