Pelvic inflammatory disease (PID) is an infection-related inflammatory spectrum spanning from uterine cervix to the peritoneal cavity, caused by ascending infections from the lower genital tract. Etiology is often polymicrobial, Chlamydia trachomatis and Neisseria gonorrhoeae being the main pathogens. Disease manifestations are numerous: cervicitis, endometritis, salpingitis, pyosalpinx, oophoritis, tubo-ovarian abscess. Pelvic peritonitis and ovarian vein thrombophlebitis represent life-threatening complications. Clinical symptoms vary depending on disease severity. Paucisymptomatic patients may manifest atypical symptoms such as anomalous vaginal discharge, metrorrhagia, intermenstrual/postcoital bleeding, dyspareunia, dysuria, pollakiuria; conversely, acute pelvic pain and fever characterize full-blown PID. The diagnosis is mainly clinical, cervical, uterine or adnexal tenderness being suggestive signs at physical bimanual examination. Laboratory tests aim to search for etiologic agents. Imaging methods are useful in equivocal cases, to rule out differential diagnoses and in the suspicion of complications. Computed tomography (CT) plays a pivotal role in emergency care settings. Most common CT findings include: peritoneal effusion, fallopian tube thickening and dilatation with wall enhancement, enlarged cervix, uterus and ovary, cystic multilocular adnexal mass, perivisceral fat stranding and pelvic ligaments thickening. However, diagnostic assessment should not delay treatment, since a prompt therapy reduces the risk of sequelae (infertility, ectopic pregnancy and chronic pelvic pain).