The aim of this study was to examine the changes that occur in the oral health attitudes and behaviors of dental students in Istanbul, Turkey, during their dental education. The Turkish version of the Hiroshima University-Dental Behavioral Inventory (HU-DBI) was distributed among 757 dental students at the Dental Faculty, Istanbul University. The response rate was 72 percent. Chi-square and logistic regression models were used for statistical analysis. The mean HU-DBI score of the clinical students was significantly higher than that of the preclinical students. Preclinical students significantly more often believed that it was impossible to prevent gum disease with toothbrushing alone and worried about the color of their teeth and bad breath. Most of them brushed their teeth with strong strokes, thought the condition of their teeth was getting worse despite daily toothbrushing, and would seek dental care only when symptoms arise. Clinical students more often used disclosing solutions to see how clean their teeth were and complained of bleeding gums. The variation in favorable oral health attitudes/behaviors appeared to reflect the students' educational training experience. The findings of this study highlight the relatively poor oral health behaviors of Turkish dental students, which should be improved by means of comprehensive programs that aim to promote their own dental hygiene practices and preventive oral health knowledge from the start of dental training.