Amebic colitis and amebic liver abscess were diagnosed in a 45-year-old patient who had returned from Thailand. Ultrasound scans performed after starting treatment with metronidazole showed an abscess located above the right kidney that had enlarged to a maximum diameter of 9.7 cm. Since rupture of this lesion was felt to be imminent, ultrasound-guided needle biopsy was performed and 300 ml of abscess fluid evacuated. The patient experienced rapid relief of his symptoms. The role of ultrasound imaging in the diagnosis and follow-up of amebic liver abscesses and the indications for ultrasound-guided needle aspiration are discussed.