Early and accurate diagnosis is difficult in clinical practice as the onset of iliopsoas abscess is commonly characterized by nonspecific symptoms. The coexistence of iliopsoas abscesses and prosthetic joint infections is extremely rare. In this case, we report a case of iliopsoas abscess mimicking adnexal mass after total hip arthroplasty (THA). A 52-year-old G2P2 woman visited the emergency department because of pain in the right lower quadrant of the abdomen. Gynecological and ultrasound examination showed a complex adnexal mass measuring 10×6 cm. The patient underwent THA for the right hip due to a failed treatment of collum femoris fracture 7 years ago. Laparotomy revealed a mass originating from the extrapelvic portion of the right iliac muscle. Intraoperative orthopedic consultation was necessitated. The solid mass was completely shelled out from the anterior abdominal wall. Though rare in incidence, we recommend that advanced imaging modalities such as computed tomography or magnetic resonance imaging could be performed as routine preoperative imaging on patients presenting with adnexal mass if there is a clinical history of hip arthroplasty.Keywords: Adnexal mass, infected total hip arthroplasty, ovarian tumor, pelvic pain, psoas abscess, surgery.