Objective: At the present time patients in developed countries widely use online resources to access medical information. YouTube is a widely used website to get knowledge. In the past, medical and dental data were accessed only by doctor and dentist examinations. This research was aimed to assess the quality and quantity of the knowledge content in popular YouTube™ videos about laser root canal treatment (LRCT). Method: Google Trends showed that "laser root canal treatment" was the most searched keyword on the topic. Included videos were assessed as the video's name, universal resource locators, the number of video display, time of adding in website, total numbers of likes, dislikes and comments and total video time. Each video was classed into the 3 groups according to their information source as dentist, commercial, dental clinic. This video was classified according to the quality of information content as ‘good’, ‘poor’, or ‘bad’. In the evaluation of the data, the distribution of variables was examined with the Shapiro-Wilk normality test, the intergroup comparison of variables that did not show a normal distribution was examined with the Kruskal Wallis test. Comparison of subgroups was examined with Dunn's multiple comparison test and comparison of qualitative data was analyzed with Chi-square test. The results were evaluated at the significance level of p