The surgical treatment of Chiari I malformation is to carry out a sub occipital decompression. It is described that postoperative complications may occur, especially if the dura is open and closed using a graft (duraplasty). Among them, one of the most important events due to its difficult handling is cerebrospinal fluid leak through the suture line. Objective. To conduct a postoperative review to analyze the outcome of the patients and the occurrence of complications depending on the dural plasty used. Material and methods. A retrospective study was carried out between 1997 and 2008, both inclusive, where we assessed 36 patients. All of them were studied with preoperative and postoperative craneoespinal magnetic resonance, and by a thorough clinical examination performed before and after the surgery. The surgical procedure consisted of sub occipital decompression and resection of the posterior arch of C1 or C1 and C2 (depending on the extent of the caudal displacement of the tonsils), followed by duraplasty using either an autologous graft (pericranium) or a synthetic graft (Gore-tex). Results. After a mean follow-up of 2 years, the clinical results were: excellent (55%), if there was a great clinical improvement; good (29%), if there was slight improvement; and bad (16%), if there was no improvement or there was worsening. In the 30 patients given a duraplasty (18 with an artificial graft, 12 with an autologous pericranium graft), 6 cases of cerebrospinal fluid leak appeared, although no significant association between the type of dural plasty and the presence of leak was observed. Conclusions: The best results were obtained for headaches, cervical pain and dizziness. Despite the fact that there were more cases of cerebrospinal fluid leak in patients receiving an artificial graft compared to patients with pericranium graft, there was no significant difference.