Vascular hamartomas are defined as disorganized and excessive proliferations of vascular tissue which, due to their limited growth, are considered developmental malformations and not true neoplasms.Vascular hamartoma of the choroid plexus, not associated with clinical signs, was diagnosed in a one year old female beagle. The mass was present within the third ventricle and was approximately 1x1 mm in diameter. Microscopically, it was composed of an expansile unencapsulated proliferation of variably sized vascular channels surrounding mildly compressed centrally scattered adipocytes. The vascular lumens were generally obscured and lined by flattened endothelial cells. Endothelial cells were positive for Factor 8 and actin. Although there was no associated compression, a mild gliosis was present in the adjacent neuropil.