High-repetition-rate laser action, up to 2 kHz, has been demonstrated in XeF molecules at 351 and 353 nm by using a blowdown fast transverse-flow system and a four-circuit, thyratron-switched, low inductance pulse generator. Fora typical run, the transverse flow was uniform, and the average flow velocity was 25 mls across a discharge region of 1.4 × 0.4 × 30 cm 3. The gas mixture used was He:Xe:NF3 = 100:1.5 :0.5, and the total pressure was varied from 600–1200 torr. For single-pulse operation, the maximum laser output energy was 22 mJ/pulse, and the electric efficiency was 0.4 percent. For a 2-kHz repetition rate, the average laser output energy was approximately 12 mJ/pulse with 50 percent variations. Hence, an average output power of 24 W was obtained. Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.