Adnexal masses are growths that form near the uterus; the majority being ovarian tumours. Although there is no established population-screening tool for detecting ovarian cancer, ultrasound and contrast-enhanced computed tomography (CECT) are useful imaging tools in the management of adnexal masses. Our study aimed to determine the characteristics of malignant adnexal masses on CECT scan and to describe common pitfalls in diagnosis of ovarian cancer when interpreting images. We also determined the sensitivity and specificity of diagnosing ovarian cancer using CECT. A retrospective study was conducted in Hospital Serdang using data from all patients who underwent CECT scan and detected with adnexal masses, and had histopathological examination correlation from January 2013 until January 2015. Out of the 64 cases analysed; the majority of malignant lesions were serous carcinoma of the ovary (40%). The CECT scan characteristics, tumour consistency of mixed type, presence of wall enhancement, septations, ascites and peritoneal nodule/omental caking were significantly associated with ovarian malignancy (p<0.05). The sensitivity, specificity, PPV and NPV of CECT scan was 95.45%, 71.43%, 63.63% and 96.77% respectively. Contrast-enhanced computed tomography scan is a good, non-invasive method to diagnose ovarian cancer. By using a pro-forma document as a guide, good results can be achieved to help differentiate between benign and malignant lesions. Nevertheless, caution needs to be exercised in interpreting cases that mimic features of malignancy. © 2017 Universiti Putra Malaysia Press.