Background and Aims: Preserving intact coronal and radicular tooth structure is considered to be crucial for the optimal biomechanical behavior of restored teeth .The ferrule effect has been extensively studied and still remains controversial from many perspectives. The purpose of this study was to summarize the results of different issues related to the ferrule effect and published in journals listed in Pub Med. Materials and Methods: The search was conducted from 1985-2014 from Pub Med and scientific dentistry internal journals using the following key words: Ferrule, Ferrule effect, Literature review, Fracture resistance, Fatigue, Finite element analysis. Results: The finding showed that the presence of 1.5-2 mm high and 1mm thickness ferrule had a positive effect on the fracture resistance of endodontically treated teeth. Conclusion: The presence of ferrule effect is essential for successful endodontic treatment. If a ferrule can performed, the teeth will have poor prognosis for survival.