The study compares MNI coordinates determined using SPM2 and FSL/FLIRT with the ICBM-152 template to Talairach coordinates determined using a landmark-based Talairach registration method (TAL). The analysis reveals significant differences in reference frames (position, orientation) and scaling (brain size) between the two coordinate systems. ICBM-152-fitted brains are consistently larger, oriented more nose down, and translated slightly down relative to TAL-fitted brains. Whole-brain analysis shows an ellipsoidal pattern of coordinate disparity, ranging from zero at deep points within the left hemisphere to over 1 cm for some anterior brain areas. The mni2tal transform generally reduces disparity for inferior brain areas but increases it for anterior, posterior, and superior areas. The best-fit MNI-to-Talairach (MTT) transform, formulated using a least-squares method on 100 high-resolution 3-D MR brain images, significantly reduces coordinate disparity, reducing group mean disparity from 5-13 mm to 1-2 mm for both deep and superficial brain sites. This transform provides a validated method to convert MNI coordinates to Talairach-compatible coordinates for studies using either SPM2 or FSL/FLIRT with the ICBM-152 template.The study compares MNI coordinates determined using SPM2 and FSL/FLIRT with the ICBM-152 template to Talairach coordinates determined using a landmark-based Talairach registration method (TAL). The analysis reveals significant differences in reference frames (position, orientation) and scaling (brain size) between the two coordinate systems. ICBM-152-fitted brains are consistently larger, oriented more nose down, and translated slightly down relative to TAL-fitted brains. Whole-brain analysis shows an ellipsoidal pattern of coordinate disparity, ranging from zero at deep points within the left hemisphere to over 1 cm for some anterior brain areas. The mni2tal transform generally reduces disparity for inferior brain areas but increases it for anterior, posterior, and superior areas. The best-fit MNI-to-Talairach (MTT) transform, formulated using a least-squares method on 100 high-resolution 3-D MR brain images, significantly reduces coordinate disparity, reducing group mean disparity from 5-13 mm to 1-2 mm for both deep and superficial brain sites. This transform provides a validated method to convert MNI coordinates to Talairach-compatible coordinates for studies using either SPM2 or FSL/FLIRT with the ICBM-152 template.