Diffusion-weighted (DW) imaging provides a new contrast mechanism for evaluation of tumors of the chest, abdominal, and pelvis. By imaging microscopic motion of water molecules, DW imaging yields new qualitative and quantitative information about tumors that can be used to improve tumor detection, characterize some tumors, and monitor and predict response to treatment. DW imaging techniques provide a host of new tools for the body imager including: magnitude DW images; ADC maps with quantitative analysis; and volumetric display of data including whole body diffusion with background suppression. Experience with these DW techniques for body applications is still accumulating. However, DW imaging has already become an integral part of body MR imaging protocols at many centers.