The patient with an abscess in the area of the right femur was initially admitted to hospital in September 2018 after ERCP (endoscopic retrograde cholangiopancreatography), which was indicated due to choledocholithiasis. Later in October 2018, the patient was readmitted to the hospital for fever, right inguinal pain, urinary disorders and mobility problems. Results of cultivations were negative, and the source of fevers was searched. On the CT of right coxa, an abscess in the area of several muscles was diagnosed, first in the paraduodenal area, later in the area of m. iliopsoas, m. tensor fasciae latae, m. sartorius dx. and m. rectus femoris. Because of the past ERCP examination with EPS (endoscopic papilosfincterectomy), this abscess was recognised as a possible ERCP complication, when the abscess came initially from the duodenum through retroperitoneum to the area of the right femur. The patient was treated with antibiotics and immediately consulted with a surgeon, then moved to the Department of Surgery, where an incision and drainage of the abscess was made; meanwhile, antibiotics were changed according to microbiological results. Later, new CT showed massive regression of the abscess, and clinical and laboratory findings improved as well as. The patient was discharged from the hospital.