Background: There are differences between sources describing reference diagnostic levels for chest computed tomography (CT). The doses are expressed either in weighted CT dose index (CTDIvol) concerning dose per slice, dose–length product (DLP), and effective dose (E). The purpose of this study was to analyse the differences in the dose levels during different protocols of routine CT chest examinations. Doses from low dose chest CT were compared to chest x-ray doses. Material and Methods: CTDI vol i DLP doses were taken to analysis from routine CT chest examinations (64 MDCT TK LIGHT SPEED GE Medical System) performed in 248 adult patients with FBP reconstruction: 51 low dose, 106 helical without contrast media, 46 with contrast media, 20 angio CT, 25 high resolution CT, as well as 19 helical without contrast media, 12 with contrast media when iterative ASIR reconstruction was used. Results: Mean values of CTDIvol and DLP had a value of 2,1mGy and 85,1mGycm for low dose, 9,7mGy and 392,3mGycm for helical without CM, 9,6mGy and 386mGycm for helical with CM, 18,2mGy and 813,9mGycm for angio CT, 2,3mGy and 64,4mGycm for high resolution CT, 8,9mGy and 317,6mGycm for helical ASIR without CM , 8,8mGy and 310,13mGycm for helical ASIR with CM. There were disclosed the significant lower doses within CTDIvol and DLP for low dose and high resolution CT versus all above CT protocols and lower doses for CT ASIR protocols (80-81%). The ratio between medial dose in low dose CT and chest x-ray was 11,56. Conclusions: The use of iterative reconstructions plays an important role In dose decreasing In computed tomography. According to our results as well as results from other authors efforts towards further dose reduction and replacing chest x-ray with low dose CT in certain research screening projects should be encouraged.