Losses have been measured at 257.2 nm ine‐beam‐pumped, KrF laser mixtures at pump rates up to 4 MW/cm3and pressures up to 3000 Torr. A maximum absorption of 3.5% cm−1is observed in a gas mixture of 4‐Torr F2, 125‐Torr Kr, and 2871‐Torr Ar. Losses are reduced in the presence of lasing. The absorption cross section of Kr2F* at 257.2 nm is estimated to be 1.8(±1.1)×10−17cm2. Net gain has been measured as a function of pump rate in a gas mixture of 4‐Torr F2, 125‐Torr Kr, and 1371‐Torr Ar. A net gain of 22% cm−1and a gain to nonsaturable loss ratio ∼20 have been observed.