OBJECTIVE Dental pain and anxiety are important factors that prevent patients from seeking dental care. The aim of this study was to assess the relationship between trait anxiety and state anxiety and also to determine the effects of age and sex on pain perception after periodontal flap surgery. METHODS In this descriptive-analytical study, 50 patients who need periodontal flap surgery were assessed in a private periodontal specialty clinic in Babol city. The amount of anxiety was measured by the Spielberger State-Trait Anxiety Inventory test, and visual analog scale scores were used for postsurgical pain perceptions in 7 times (immediately after surgery and days 1-6 after surgery). Data were analyzed and evaluated by SPSS V22.0 software (IBM, United States). RESULTS In the trait anxiety study, there was a significant difference in pain perception between different anxiety classes at times immediately after surgery, 1st day, and 2nd day after surgery (P < 0.05), and in the state anxiety study, there was a significant difference in pain perception between different anxiety classes at times immediately after surgery until the 5th day after surgery (P < 0.05). Furthermore, the results indicate that the pain perception in female was significantly higher than male, at times immediately after surgery, 3rd day, and 5th day after surgery (P < 0.05). However, there was no association between age and pain perception in different times (P > 0.05). CONCLUSIONS Anxiety is associated with pain perception following periodontal flap surgery, and female experience more pain after surgery, whereas the amount of pain perception is not related to age.