Aim: Many studies reported that the degree of tonsillar herniation does not correlate with the severity of symptoms in Chiari Malformation Type 1 patients. The aim of this study is to investigate the relationship between tonsillar herniation, Cerebrospinal Fluid (CSF) flow and Somatosensory Evoked Potentials (SEP) in Chiari Malformation Type 1 patients. Material and Method: We have retrospectively reviewed 27 patients which had Chiari Malformation at our clinic. There were 7 men (25.3%) and 20 female (74.1%) with a mean age of 38 (range 15-62) years. Results: Fourteen patients (51.9%) had tonsillar ectopia 0-5mm, 13 patients had tonsillar ectopia over 5mm (48.9%). CSF flow abnormality was found in 13 patients (48.1%) and SEP abnormality in 6 patients (22.2%). In all patients clivus, supraoccipital, cerebellum hemisphere, Mc Rae line, Twinning line lengths and tentorium Twinning angle, Welcher basal angle, Boogaard angle were measured. There was no significant difference between tonsillar ectopia degree and abnormal SEP. Six patients who had abnormal SEP also had CSF flow abnormality (p<0.05). There was a significant difference between SEP and platybasia (p<0,05). Of the 27 patients, 5 were operated. There was statistical difference between CSF flow, tonsillar ectopia, and surgery (p<0.05). Discussion: The presence of CSF flow disorder in Chiari symptomatic patients is a finding of a hypopiastic posterior fossa. CSF flow disorder was associated with tonsillar ectopia. Despite the high rate of platybasia in patients with SEP disorder, more studies should be done in the future.