Acute left lower quadrant pain is frequently caused by diverticulitis, especially in elderly patients. The most common differential diagnoses include renal colic, urinary tract infection, gynaecologic disorders, epiploic appendicitis, perforated carcinoma, other inflammatory diseases of the colon and diseases of the abdominal wall. Because the clinical impression may lead to a false diagnosis, further evaluation is necessary. Imaging methods are used to establish a correct diagnosis and to differentiate between benign self-limited disorders and those which require immediate intervention. Sonography and CT are the imaging methods of choice for the examination of patients with left lower quadrant pain. Both methods have shown to be accurate in verifying diverticulitis as well as in establishing alternative diagnoses. This review reports the sonographic appearance of the different entities and refers to other imaging methods if necessary.