Background. Positron emission tomography (PET) is commonly used to detect occult or recurrent malignancy, including tumors of the female genital tract. Recently, there have been reports of PET scans used in patients with Gestational Trophoblastic Disease (GTD). Case. A 22-year-old female presented with vaginal bleeding and elevated β-hCG 7 months after a spontaneous vaginal delivery of a healthy infant. She had a history of molar pregnancy and persistent GTD requiring multi-agent chemotherapy. Metastatic evaluation with computed tomography and magnetic resonance imaging showed no evidence of GTD. A positron emission tomography/computed tomography (PET/CT) scan revealed a focus of metabolic activity in the left pelvis. The patient underwent an exploratory laparotomy that revealed metastatic choriocarcinoma in the left broad ligament. Conclusion. PET/CT may be useful in the evaluation of occult choriocarcinoma when conventional imaging fails to identify metastatic disease. © 2005 Elsevier Inc. All rights reserved.