Bone mineral density and three-dimensional trabecular structure play a significant role in predicting bone strength and biomechanical properties. MR is a non-invasive technique for determining trabecular architecture both in vivo and in vitro. In this paper we review the use of magnetic resonance imaging to obtain high resolution images of trabecular bone structure and quantify the three-dimensional architecture of the trabecular bone network. Studies assessing the anisotropy of the trabecular architecture in human cadaveric specimens from the distal and proximal femur, and the thoracic and lumbar vertebrae, are reviewed. The contributions of the MR derived measures of 3D trabecular bone structure to the biomechanical strength of the specimen are presented. In vivo, the relationship between the high resolution MR derived trabecular bone structure parameters in the distal radius and calcaneus in patients with hip fractures, are compared to age matched normal controls. MR derived measures are compared to measures of trabecular bone mineral density (BMD) in the hip using dual X-ray absorptiometry (DXA).