Aim To assess specificity and sensitivity of the clinical and radiographic diagnoses of cystic jaw lesions in relation to the histology-based final diagnoses, and evaluate characteristics of cystic jaw lesions treated in a university hospital over a 6-year period. Material and Methods Retrospective analyses of clinical, radiographic and histopathological records of 166 patients diagnosed with, and treated for, cystic jaw lesions at the Department of Oral and Maxillofacial Surgery, Aarhus University Hospital from 2005 to 2010. Results Specificity was generally high for all cystic jaw lesions, but a low diagnostic sensitivity in relation to the keratocystic odontogenic tumour (KCOT) was revealed. The radicular cyst, dentigerous cyst and KCOT were the most frequently observed cystic jaw lesions. Conclusion In general, a high diagnostic specificity for all cystic jaw lesions was observed. A low diagnostic sensitivity for KCOT was revealed, which is the major reason why histology-based final diagnoses should be regarded as the gold standard whenever KCOT is to be included in the differential diagnosis of cystic jaw lesions. Frequency of cystic jaw lesions in the present study was in agreement with previous studies.