BACKGROUND Jaw bones might be potential locations for different lesions. Differences in prevalence and the type of lesions can help in designing and programming prevention procedures in health care centers. OBJECTIVES The aim of the present study was to evaluate the prevalence of intraosseous lesions in the jaws of patients referred to diagnostic and therapeutic centers in Hamadan during 1990-2010. PATIENTS AND METHODS This cross-sectional descriptive analytical study was carried out in Hamadan in 2011. Data sheets of the subjects were used to collect all the data of patients with intraosseous lesions, including their age, gender, location of the lesion, the radiographic view of lesions, and their type and histopathological diagnoses. Data were analyzed with SPSS, using means and frequencies. RESULTS A total of 284 intraosseous lesions were reported in our study. The mean age of the subjects was 28.8 ± 15.2 years. The lesions were distributed in males and females almost similarly. The most prevalent lesions were cystic lesions (54.58%), manifestations of systemic conditions in jaw bones (18.3%), benign tumors (15.5%), malignant lesions (6.7%), and inflammatory lesions (4.92%), in a descending order. The most common cystic lesion was radicular cyst; the most common manifestation of systemic conditions in jaw bones was central giant cell granuloma; the most common benign tumor was ameloblastoma; the most common malignant lesion was osteosarcoma; and the most common inflammatory lesion was periapical granuloma. CONCLUSIONS Our data provided information on the prevalence and types of intraosseous lesions among an Iranian population. This study provided baseline information to help in designing and programming procedures in health care centers in every community so that preventive therapeutic measures can be adopted.