Ovarian cancer is the second most frequent gynecologic malignancy (preceded by cervix carcinoma) with up to 25 and 75 % chance of 2 years’ recurrence of early and advance stages respectively. PET is a tomographic scintigraphic technique in which a computer-generated image of local radioactive tracer distribution in tissues is produced through the detection of annihilation photons that are emitted when radionuclides introduced into the body decay and release positrons. 18F-FDG PET is a tomographic imaging technique that uses a radiolabeled analog of glucose, 18F-FDG, to image relative glucose use rates in various tissues. Because glucose use is increased in many malignancies, 18F-FDG PET is a sensitive method for detecting, staging, and monitoring the effects of therapy of many malignancies. CT is a tomographic imaging technique that uses an x-ray beam to produce anatomic images. This anatomic information is used to detect and to help determine the location and extent of malignancies. Combined PET/CT devices provide both the metabolic information from 18F-FDG PET and the anatomic information from CT in a single examination. Ovarian cancer is the fifth leading cause of cancer death among women in the United States and has a high likelihood of recurrence despite ag- gressive treatment strategies. Detection and exact localization of recur- rent lesions are critical for guiding management and determining the proper therapeutic approach, which may prolong survival. Because of its high sensitivity and specificity compared with those of conventional techniques such as computed tomography (CT) and magnetic reso- nance (MR) imaging, fluorine 18 fluorodeoXyglucose positron emission tomography (PET) combined with CT is useful for detection of recur- rent or residual ovarian cancer and for monitoring response to therapy. However, PET/CT may yield false-negative results in patients with small, necrotic, mucinous, cystic, or low-grade tumors. In addition, in the posttherapy setting, inflammatory and infectious processes may lead to false-positive PET/CT results. Despite these drawbacks, PET/CT is superior to CT and MR imaging for depiction of recurrent disease.