OBJECTIVE: To examine the influence of race, gender, and socioeconomic factors on presentations and outcomes of adult Chiari I malformations. METHODS: The charts of 638 adult patients with Chiari I malformations were reviewed, and 287 patients were included in the study. Race, gender, insurance status, symptoms, depth of cerebellar tonsillar herniation, and presence of syringomyelia were examined as covariates in multivariate logistic regression models to identify independent predictors of presentation and outcome. RESULTS: Patients with public insurance had a longer stay in the hospital (P = 0.01). A higher proportion of male patients presented with upper extremity weakness (P = 0.01), lower extremity weakness (P = 0.040), and cranial nerve findings (P = 0.02). Men had shorter onset to diagnosis times (P = 0.02), worse tonsillar herniation (P = 0.03), and more severe symptoms (P = 0.05). White patients more frequently presented with back pain (P = 0.03), and African American patients more frequently presented with lower extremity weakness (P = 0.01). African Americans had worse tonsillar herniation (P < 0.01) and were more likely to present with syringomyelia (P = 0.01). Multivariate regression analysis revealed that back pain (P < 0.01), upper extremity weakness (P ≤ 0.01), upper extremity paresthesias (P < 0.01), and upper with lower extremity paresthesias (P = 0.04) were significant predictors of syringomyelia. The only independent predictor of outcome was size of tonsillar herniation (P = 0.03). CONCLUSIONS: Significant differences in presentation of Chiari I malformation resulting from gender, race, and insurance status were quantified for the first time.