Introduction: Dental Anxiety is one of the important reasons of people’ s avoidance from dental care and in long-term, in turn leading to decreased oral and dental health level and quality of life. On the other hand, the occurrence of anxiety in patients and repeated examination of them affects dentist’ s performance. Objective: The purpose of this study was the evaluation of anxiety and related factors in adult patients referred to the Dental School, Guilan University of Medical Sciences in 2015-2016. Materials and Methods: In this cross-sectional study, random sampling methods on 200 patients referred to the Guilan Dental School was done. Data including information obtained from 4 questionnaires 1-referred testimonial, 2-personal information and other research index and relative factors, 3-Dental Anxiety questionnaire (Corah) (DAS), 4-Personal satisfaction of quality of life (MC Grath) were collected and analysed. Using SPSS software and application of satisfaction T tests, Variance Analysis ANOVA, spearman and Pearson correlation coefficient, the results were analyzed (p<0. 05) Results: The results showed that 83 persons, i. e, 41. 5% of samples had slight dental anxiety, 78 persons (39%) had average dental anxiety and 39 persons, (19. 5%) were with severe dental anxiety. In this study, female patients exhibited a higher level of dental anxiety, compared to male counterparts. A significant association was revealed between the level of dental anxiety and level of education. Conclusion: This study showed that most patients referred to the center were with dental anxiety. Also, the results showed a significant relationship between dental anxiety level and related factors such as other relative factors including sex, age, level of education, personal satisfaction of quality life, number of dental visit and etc.