This paper is a review of digital radiography, the application of digital electronic technology to medical X-ray imaging. At some stage in the formation of an image the detected X-ray fluence is converted into a digital format for processing and display. In many X-ray procedures digital methods offer considerable advantages over previously used techniques in speed, precision, flexibility, sophistication of processing, or other characteristics. These in turn can lead to reductions in degree of invasiveness, X-ray exposure, or contrast material dose or certain other advantages such as reduced time per X-ray procedure. The major digital X-ray imaging techniques are discussed, ranging from contrast enhancement to image subtraction schemes to more recently developed methods such as temporal filtering of image sequences at realtime video rates. Digital imaging systems are categorized according to detector geometry, and the relative merits of each are discussed. Examples of clinical applications are given.