Imaging of the paranasal sinuses, including plain film radiography, CT, and MRI, is unnecessary in patients who meet the clinical diagnostic criteria for uncomplicated acute rhinosinusitis. Acute rhino-sinusitis is defined as up to four weeks of purulent nasal drainage (anterior, posterior, or both) accompanied by nasal obstruction, facial pain-pressure-fullness, or both. Imaging is costly and may expose patients to radiation. Imaging may be appropriate in patients with a complication of acute rhinosinusitis, patients with comorbidities that predispose them to complications, and patients in whom an alternative diagnosis is suspected.