Objective: The ultimate anatomy of the Meyer's loop continues to elude us. Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) may be able to demonstrate, in vivo, the anatomy of the complex network of white matter fibers surrounding the Meyer's loop and the optic radiations. This study aims at exploring the anatomy of the Meyer's loop by using DTI and fiber tractography. Methods: Ten healthy subjects underwent magnetic resonance imaging (MRI) with DTI at 3 T. Using a region-of-interest (ROI) based diffusion tensor imaging and fiber tracking software (Release 2.6, Achieva, Philips), sequential ROI were placed to reconstruct visual fibers and neighboring projection fibers involved in the formation of Meyer's loop. The 3-dimensional (3D) reconstructed fibers were visualized by superimposition on 3-planar MRI brain images to enhance their precise anatomical localization and relationship with other anatomical structures. Results: Several projection fiber including the optic radiation, occipitopontine/parietopontine fibers and posterior thalamic peduncle participated in the formation of Meyer's loop. Two patterns of angulation of the Meyer's loop were found. Conclusions: DTI with DTT provides a complimentary, in vivo, method to study the details of the anatomy of the Meyer's loop. Meyer's loop is commonly known as the temporal loop of the anterior fibers of the optic radiation that originate in the lateral geniculate body and course anteriorly, into the temporal lobe, before turning posteriorly to reach the occipital visual cortex. Adolf Meyer applied histological, brain lesion studies to describe this peculiar course into the temporal lobe of the visual projection fibers, in 1907 [1]. Histological staining techniques that are applicable in humans provide an ambiguous visualization of the myelinstained white matter fibers and are limited by an inability to precisely trace and reconstruct the course of these fibers. Therefore, the composition and course of the Meyer's loop, or the fact that this temporal loop is composed exclusively by the optic radiation fibers remains unclear.A unique 3D perspective on the white matter architecture can be achieved by applying the fiber dissection technique, but with this technique it is difficult to differentiate individual visual projection fibers, because of the intrinsic limitations of this technique to distinguish and trace individual fibers among the complex network of many neighboring fibers [2,3]. Furthermore, the delineation of the Meyer's loop using the fiber dissection technique is challenging and its exact fiber composition and location are a point of controversy. Knowledge of the anatomy of the Meyer's loop is essential for minimizing the risk of damaging this structure during surgery for temporal lobe lesions and epilepsy. However, the ultimate anatomical details of the Meyer's loop remain even today obscure, because both histological and fiber dissection techniques are less suitable to accurately demonstrate its precise fiber composition and exact lo...