A seminal vesicle cyst is a rare etiology of pelvic pain. However, its rarity may result in oversight or misinterpretation if the radiologist or emergency physician is unfamiliar with this entity. Seminal vesicle cysts may cause pelvic pain because of mass effect, infection, internal hemorrhage, or urinary and bladder obstruction. Because seminal vesicle cysts rarely result in physical examination findings or laboratory abnormalities, pelvic computed tomography plays a pivotal role in their diagnosis and in evaluating patients with pelvic pain. Recognition of the imaging findings of seminal vesicle cysts is necessary to allow prompt, accurate diagnosis. Therefore, emergency physicians and radiologists interpreting examinations from the emergency department should be familiar with these imaging findings because seminal vesicle cysts may be the etiology of pelvic pain and the patient may benefit from urologic consultation and cyst aspiration or resection. The purposes of this article are to provide examples of pelvic pain caused by seminal vesicle cysts, illustrate the key imaging findings on computed tomography, and briefly review the literature.