The size of brain ventricles are especially relevant in some brain diseases such as epilepsy, schizophrenia and other neurodegenerative diseases. For this reason, the size of the brain ventricles has been the subject of many studies none of which has estimated total ventricles volume and volume fraction. The purpose of our study is to estimate the volume and volume fraction data related to the fourth, third, lateral ventricle. The volumes of fourth, third, lateral ventricle was estimated in 14 Turkish young volunteers (7 males and 7 females), aged between 18 and 36 who are free of any neurological symptoms and signs, using serial magnetic resonance (MR) images. The volumes of subjects were determined on MR images using, the point-counting and planimetry methods.