Objective: The aim of this study was to evaluate the anxiety levels of patients attending a university oral diagnosis clinic. Avoidance, felt physiologic responses, and the most fear-producing stimuli of dental treatment were also evaluated. Method and Materials: A total of 1,437 patients were asked to complete a questionnaire consisting of the Dental Anxiety Scale (DAS), Dental Fear Scale (DFS), and questions about age, gender, education level, and frequency of dental visits. The patients were grouped according to gender and divided into 5 age categories. Statistical analysis was made by descriptive statistics, two-proportion z test, analysis of variance, Tukey's Honestly Significant Difference test, and Scheffe test. Results: The mean DAS score was 9.52 (SD 4.08) for females, 7.96 (SD 3.30) for males, and 8.76 (SD 3.80) for the total sample. There was no statistically significant difference between the mean DAS scores of age groups: Patients with a primary school education and those who had never visited the dentist had the highest anxiety scores. According to the DFS, the most felt autonomic response was increased heart rate, and the most fear-producing stimuli were the sight of the needle (25.1 %) and sensation of the injection (24.1 %). Of the patients 10.5% avoided calling for an appointment, and 4.9% canceled or did not appear for appointment. Conclusion: Some patients are afraid of some of the stimuli involved with dental treatment. This could affect the patient-dentist relationship and the dental treatment plan; therefore, before dental treatment, patients' anxiety and fear levels should be assessed.