This review aims to evaluate the definition, reason, and management of postoperative pain during and/or after endodontics treatment. Postoperative pain is very common and its prevalence ranges between 3% and 58% of all endodontic patients and they usually evaluate postoperative pain as a skill criterion of the clinician. Postoperative pain is multifactorial and observed as a result of acute periapical inflammation in response to chemical, mechanical, and/or microbial damage of the periapical area during the endodontic treatment. Therefore, patients should always be informed that pain may be experienced after the procedure and clinicians should follow up-recent studies about the factors that may cause pain, and if possible, adapt clinical procedures accordingly.