X‐ray laser gain in laser‐produced plasmas for collisionally pumped 3p‐3stransitions in neon (Ne)‐like krypton ions has been estimated. The dependence of the gain on the temperature‐dependent average ionic charge stateZ¯(Te) and the fraction &dgr;(Te) of Ne‐like ions evaluated by using the plasma ionization model has been studied. It is observed that the temperature dependence of these parameters has a profound effect on the gain estimate, showing the importance of including the ionization model precisely for accurate modeling of x‐ray laser gain. ©1995 American Institute of Physics.