Objective: To investigate the prevalence of persistent pain of neuropathic origin after nonsurgical root canal treatment and to determine its characteristics, location, and severity utilizing a self-reported validated postal survey. Method and Materials: A modified version of the Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) survey was mailed to 2,338 adult subjects who received a single-tooth nonsurgical root canal treatment at the University of Illinois at Chicago College of Dentistry Postgraduate Endodontics Clinic over a 4-year period. Two-hundred and fifty (10.7%) completed surveys were returned. Descriptive analysis, Pearson correlation to determine correlations between the S-LANSS scores and variables of interest, and t tests for group comparisons of the S-LANSS score were performed. Statistical significance was determined at P .05. Results: The prevalence of persistent pain of neuropathic origin among respondents after receiving single-tooth nonsurgical root canal treatment was 7% with the average pain reported as 7.2 on a visual analogue scale (where 0 is no pain and 10 is pain as severe as it could be). Neuropathic pain was more common in middle-aged (mean 50.6 years of age) individuals with no sex predilection and occurred more frequently in the mandibular arch without any differences attributable to the number of canals treated. Also, the majority of subjects most frequently endorsed their pain experiences as abnormal sensitivity to touch and pain when the area is pressed or rubbed. Conclusion: Dental providers need to recognize and understand the differences between nociceptive and neuropathic pain. Understanding these concepts will assist in preventing inappropriate, irreversible, and unnecessary interventions. Schlagwörter: neuropathic pain, nonsurgical root canal treatment, Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS)