An X-ray exposure meter has been developed for use with a 220-kv. X-ray radiographic installation at the Naval Research Laboratory. For given brands of film and intensifying screens, the meter may be calibrated to indicate the exposure times required for any desired film blackening. The dependence of this calibration on kilovoltage, specimen material, and filter technique has been investigated. In routine radiography, it is possible to obtain satisfactory results with a single calibration curve, at all voltages between 125-kv. and 200-kv., for any specimen material, and for filtered as well as unfiltered radiation. The receiving element of the exposure meter is a Geiger-Muller counter designed to permit accurate intensity determinations in a few seconds, with the measured beam of radiation limited to a pencil of X-rays, 1/4 in. in diameter. The use of a small aperture on the counter permits the scanning of portions of castings of nonuniform thickness to determine an optimum kilovoltage and suitable filter technique for radiographing. Since the counter is placed close to the film position, the meter indications are independent of variations in the source-to-film distance.