The absorption in e‐beam‐pumped Ar/Xe/F2and Ne/Xe/F2mixtures was measured using a flashlamp‐pumped dye laser at 340 nm. The photoabsorption of the active medium affects the extraction efficiency and the length scaling of the laser. The gas mixtures were excited by a 150‐keV 5‐A/cm2beam of fast electrons. The pumping conditions and gas mixtures used were typical of e‐beam‐pumped XeF lasers. Our results confirm that the absorption in Ne‐diluted mixtures is appreciably smaller than in Ar‐diluted mixtures. Data was obtained for a wide variety of mixture pressures and ratios. Using our kinetic model, the results were analyzed and the dominant absorbing species were identified.