Purpose: The aim of this study was to examine the perceived barriers to preventive dental practice among Iranian dentists. Materials and Methods: A questionnaire survey was performed among the dentists who participated in two annual dental meetings (conducted in December 2004 and in July 2005) in Tehran, Iran. The dentists who attended the meeting completed the self-administered questionnaire anonymously. The questionnaire included 12 statements with answer alternatives rated on a 5-point scale to which the dentists were asked to indicate how much each of the 12 items, later classified as three barriers (practice-, dentist- and patient-related), impedes them from practising preventive care. The sum of the scores of the four items in each barrier served as an indicator of each dentist's perception of the strength of each barrier. The background data included dentists' personal and professional characteristics. In total, 1033 dentists completed the questionnaire, of whom 980 (64% men) were eligible. Statistical evaluation was performed using analysis of variance, t test and Pearson's correlation coefficient. Results: Of the respondents, 29% to 66% rated the items of the practice-related barrier as very strong impediments. Corresponding figures for the dentist- and the patient-related barriers were 20% to 54% and 70% to 77%, respectively. The highest mean of the score sum was for the patient-related barrier (11.9) and the lowest mean was for the dentistrelated barrier (7.9). For both practice- and dentist-related barriers, male dentists reported significantly higher scores than the female dentists (P 0.001). Conclusions: The perceived barriers to the provision of preventive care should be meticulously explored and tackled to enhance oral health in Iran. Keywords: barriers against prevention, dental education, practice factors, preventive dental care