BACKGROUND: This study is focused on the histologic characteristics of occipital bone removed during Chiari I decompression in the hope of discovering unique features that may be related to the pathogenesis of this condition. METHODS: Ten consecutive pediatric patients with Chiari I malformation underwent standard posterior fossa decompression surgery. Bone that was removed from the posterior fossa was sent for histological examination. Bone from age-matched controls also underwent histological analysis. RESULTS: For all study and control specimens, bony samples were found to be made up of dense lamellar bone without marrow elements. In all aspects, histologically, the bone tissue had a normal appearance compared to control samples. CONCLUSIONS: Although many authors have mentioned that the occipital bone in patients with Chiari I malformation is abnormal on imaging or at operation (e.g., thinned, thickened), based on our study, there is no histological difference between the occipital bone removed at operation and controls.