Abstract: A system and method for automatically collimating X-rays. A digital X-ray system (100) includes a generator (108), a sensor unit (110), a control station (112), and a preview monitor (114). The generator (108) generates X-ray radiation that is captured by the sensor unit (110) as a digital image and transmitted to the control station (112). The captured image is displayed on the preview monitor (114). The generator (108) includes a collimator (212) that collimates the generated radiation into a primary beam of X-rays. The size and shape of the primary beam can be adjusted by modifying collimation parameters. A short duration beam of X-rays is generated by the generator (108) and captured (414) by the sensor unit (110). This step is repeated as necessary or desired. The resulting digital images are analyzed (418) by the control station (112) to calculate a calibration coefficient. Another short duration beam of X-rays is generated and a reference image is captured (514).