Adnexal masses have an etiological spectrum ranging from gynecologic to non-gynecologic causes. Because they can be benign or malignant, their evaluation has to include a careful analysis of the patients history, a physical examination, and laboratory and imaging tests. Transvaginal ultrasonography remains the standard for evaluation of adnexal masses. Findings suggestive of malignancy in an adnexal mass include a solid component or intracystic proliferations, thick septations (greater than 2 to 3 mm), bilateral occurrence, blood flow within the solid component of the mass, and presence of ascites. Tumor-neoangiogenesis has typical features of flow pattern and vascular architecture, indicative of malignancy, which can be visualized by Doppler ultrasound. Power Doppler with its increased sensitivity for slow flow and small vessels is ideal for this purpose and, in combination with acquisition of a volume data set of the region of interest (RoI), gives new insights in tumor angiology and appears to be an additional diagnostic tool. An important predictor of malignancy is a resistance index (RI) below 0.42 in arterial tumor vessels. 3D rendering modes like magic cut, NICHE mode, power Doppler glass body rendering, can make valuable contributions to differential diagnose of adnexal masses. A variety of adnexal masses is illustrated in their specific sonographic appearance, with special regard to ovarian carcinoma.