Magnetic resonance (MR) imaging is a complex modality that produces vast amounts of information. This information is shown as gray scale contrast derived from variations in signal intensity. Normal tissues have characteristic signal intensity patterns and contours. Alterations in tissue biochemical composition, structure, shape, and size can be detected using MR imaging and are seen as alterations in signal intensity and contour of the anatomical structures being evaluated. However, the appearance of MR images are affected greatly by the pulse sequences used in acquisition, the imaging options, and positioning of the region of interest. MR imaging is also prone to a variety of artifacts. It is therefore important that the interpreter has an understanding of the limitations of MR imaging and how best to optimize and interpret the information collected. It is also important that this information is interpreted in the light of the clinical findings and other diagnostic information for each horse.