Background: Panoramic imaging is one of the most common imaging methods in dentistry. Regarding the side-effects of ionizing radiation, it is necessary to survey different aspects and details of panoramic imaging. In this study, we compared the absorbed x-ray dose around two panoramic x-ray units: PM 2002 CC Proline (Planmeca, Helsinki, Finland) and Cranex Tome (Soredex, Helsinki, Finland). Materials and Methods: In this cross-sectional study, 15 thermoluminescet dosemeters (TLD-100) were placed in 3 semi-circles of 40cm, 80cm and 120cm radii in order to estimate x-ray dose. Around each unit, the number of TLDs in each semicircle was 5 with equal intervals. The center of semicircles accords with the patient’ s position. Each TLD was exposed 40 times. These dosemeters were read out with a Harshaw Model 4000 TLD Reader (USA). The calibration processing and the reading of dosemeters were performed by the Atomic Energy Organization of Iran. Results: The mean absorbed dose in three lines of PM 2002 CC Proline was 123. 2± 15. 1, 118. 0± 11. 0 and 108. 0± 9. 1 μ Sv, (p=0. 013). The results were 140. 4± 15. 2, 120. 2± 10. 4 and 111. 6± 11. 2 μ Sv in Cranex Tome (p=0. 208), which reveals no significant difference between two systems. Conclusion: There are no significant differences between the mean absorbed dose of surveyed models in panoramic imaging by two units (PM 2002 CC Proline and Cranex Tome). These results were less than occupational exposure recommended by ICRP, even at the highest calculated doses.