Aim To evaluate the most common pathways of fear and anxiety in patients who have had root canal treatment or are planned to have one. Methodology Six hundred and twenty-seven patients were approached to participate, of which five hundred and ninety-four patients (20-90 years) accepted. All consenting patients had a root filling or were treatment planned to have one. The survey by Ost & Hugdahl (1981) on anxiety response patterns was modified and used. Data were presented using descriptive statistics, tested for normality using the Kolmogorov-Smirnov test and analysed with nonparametric anova (Kruskal-Wallis) and post hoc test. Results Cognitive conditioning and parental pathways seem to be the primary cause (P < 0.05) of fear and anxiety with root canal treatment. Females were significantly more likely to be influenced by indirect conditioned experiences such as informative, parental, verbal threat and vicarious pathways. Conclusion The origin of patients' fears requires more attention in terms of treating endodontic-related fear and anxiety. More detailed research into the effects of demographics, causative factors and ethnicity on pathways of fear in dentistry is required to help dentists better manage patients in a multicultural society.