OBJECTIVE The anatomy and distribution of the diploic veins (DVs) of the cranial base have not been fully documented. The aim of this study was to characterize these veins using contrast magnetic resonance imaging (MRI). METHODS In total, 95 patients underwent thin-sliced, contrast MRI. Coronal and sagittal images were used for the analysis. The cranial base was divided into the anterior, middle, and posterior bases. Then, each base was further subdivided into three equal parts in the anteroposterior and lateromedial directions. The anteroposterior parts were evaluated on coronal images, while the lateromedial parts were evaluated on sagittal images. RESULTS The DVs were identified over the entire cranial base. However, they were more frequent in the posterior-third of the lateral-third region of the anterior, middle-third of the lateral and middle-third regions of the middle, and middle-third region of the posterior cranial base, and sparse in the posterior and medial-third regions of the middle cranial base. The DVs showed marked morphological variability. For instance, the DVs of the pterional area were generally well defined, as pivotal channels connecting the lateral parts of the anterior and middle cranial base, but were highly varied in appearance. CONCLUSIONS The DVs of the cranial base are distinct structures characterized by morphological variability and topographical predilection. Contrast MRI is useful for delineating these veins.