There is currently a growing interest in applications of diffusion-weighted imaging (DWI) in the abdomen and pelvis. DWI provides original functional information where the signal and contrast are determined by the microscopic mobility of water. DWI can provide additional information over conventional MR sequences, and could potentially be used as an alternative to contrast-enhanced sequences in patients with chronic renal insufficiency at risk of nephrogenic systemic fibrosis. We provide an overview on basic physics background on DWI applied to the kidneys, and we summarize the current available data, including our recent experience.