Background: Endodontic treatment failure can occur due to various factors such as persistent bacterial infection, inadequate obturation, improper coronal seal, complications of instrumentation, and untreated canals. Understanding the common causes of failure is crucial for improving treatment outcomes and preventing adverse consequences for patients and practitioners. Objective: This study aims to investigate the common causes of failure in endodontic treatments, focusing on identifying recurring issues, analyzing the impact of improper techniques or materials on treatment outcomes, and exploring the role of microbial infections in contributing to treatment failure. Conclusion: The study highlights the importance of thorough debridement to eliminate persistent bacteria, proper obturation to ensure a well-sealed canal, and a good coronal seal to prevent reinfection. Complications of instrumentation and untreated canals are also significant factors contributing to treatment failure. By adhering to preventative measures such as proper diagnosis, meticulous cleaning and shaping, effective disinfection, and quality obturation, dental professionals can enhance the success rate of endodontic treatments and minimize the risk of failure. Regular follow-up appointments and communication with patients are essential to identify and address any issues promptly, ultimately improving the long-term prognosis of endodontically treated teeth.