RF discharges at 200 MHz and 9.3 GHz have produced lasing in XeF. These discharges have been studied and appear to be well characterized by two stages. In the first stage a uniform discharge is produced inside the laser‐tube by the microwaves. During the second stage a traveling surface wave, launched by the conditions of the plasma, dominates the plasma discharge in the laser tube. This surface wave sustains a non‐uniform plasma with high electron concentration near the walls of the tube. Experimentally this non‐uniformity has been avoided in small diameter (< lmm) tubes.