The aim of this retrospective analysis was to examine olfactory disorders among the patients in the Ear, Nose, and Throat Clinic of Tampere University Hospital, Finland, from 2001 to 2011, and to evaluate the necessity of imaging in the examination of patients with olfactory disorders. Charts of 143 consecutive patients with a primary olfactory disorder were examined, and 69 patients who had undergone the necessary testing were included in the study. The most common causes of olfactory disorder were upper respiratory infection (23%), chronic rhinosinusitis (19%), head trauma (17%), and allergic or nonallergic rhinitis (6%). In 25% of the patients, no obvious cause for the symptoms was found. Computed tomography (CT) scans were normal in 37 of 52 (71%) patients and magnetic resonance imaging was normal in 21 of 25 (84%) patients. No intracranial or intranasal tumors were found in the overall cohort. Of the patients with additional symptoms (facial pain, headache, nasal discharge, or stuffiness), 58% had chronic rhinosinusitis. Of the patients with no additional symptoms or signs associated with chronic rhinosinusitis on clinical evaluation, only 2% had chronic rhinosinusitis on imaging. Only the detection of chronic rhinosinusitis and head trauma had clinical value in the determination of the etiology. A sinonasal CT scan should be considered in patients who have at least one symptom associated with sinusitis in addition to an olfactory disorder to confirm the etiology and to find those patients who may benefit from medical therapy or surgical treatment.