Conflict of interests is a situation when someone is in need of other people’s trust on one the hand and has personal or general interests on the other hand, resulting in conflict with the given responsibility. In this research work, an attempt was made to find the relation between declarations of conflict of interests and reporting positive outcomes in the dental journals in Iran. In this analytical/cross-sectional study, first Health and Biomedical Information was searched and all the Persian and English (...) dental journals published in Iran were collected. Then, all the papers published in the journals from December 2000 to December 2016 were collected and categorized in terms of the year of publication, author or authors’ affiliations, Persian and English journal, type of the substance or the drug used, declarations of conflict of interests and the positive or negative conclusion of the report. Data were analyzed with the Fisher’s exact test and Chi squared test, using the program SPSS 18. In numerical analysis, the significance was set at P < 0.05. Seventeen dental journals in Persian and English were analyzed: 10 in English and 7 in Persian. Reviewing these studies showed that of 1021 articles in Persian, in 128 cases there was no mention of a declaration of conflict of interests and in 11 cases, the COI had been stated. In addition, from 1220 articles in English, in 825 cases there was no mention of declarations of conflict of interests and in 45 cases, the declarations of COI had been mentioned. There was no significant relation between the COI and ‘no’ COI and the reporting of positive outcomes in papers in Iranian dental journals in terms of the journal type, year of publication and the journals’ guarantee form. A total of 83% of studies with declarations of COI had one positive outcome, with a significant relationship in this field; however, in 73% of studies with no COI, there was one positive outcome, too. In general, the society expects that doctors would not consider any incentives except the health of the patients in the efforts made by them. The severity of the consequences of COI is of higher value when the patients’ health is endangered due to it. In addition, COI might change the attitude and approach of other doctors and peers. (shrink)