Aim:Chiari Malformation Type I is associated with anomaly of hindbrain with displacement of the cerebellar tonsils into the upper cervical canal.The dural splitting and duraplasty are common methods which were used in the surgical treatment for the patients with Chiari Malformation Type I. In this study, we aimed to comparison two surgical methods in terms of clinical and radiological results.Material and Methods:This study includes 113 adult patients with Chiari Malformation Type I treated between 2009 and 2013 in our clinic (Erciyes University Medical Faculty,Neurosurgery Department). The patients were divided into two groups according to the surgical method(Dural splitting and Duraplasty). Neurological examinations of all the patients and Magnetic Resonance Imaging(MRI) scans were recorded periodically at 3,6,12th of the postoperative period. The tonsillo-dural distance(TDD) and regression rate of the syrinx cavity were measured on T2 and T1 sagittal MRI at the postoperative period Results: The ratio of syrinx regression was %49,6 in the Group 1 and %54,6 in the group 2. This result was statistically significant. The Tonsillo-Dural Distance increased in the group 2 and this result was statistically significant too(p<0.05). Postoperative pain and numbness decreased in the both of the groups and there was no statistical difference between the groups. Conclusion:There was no relationship between tonsillar herniation length and the width of syringomyelic cavity. The syrinx cavity more regressed in the group 2 than group 1. There was no relation between the Tonsillo-Dural Distance and the ratio of syrinx regression.