The gas-vapor bubbles oscillating in the acoustic field are considered. The diffusion of gas and vapor components inside the bubble is taken into account. The analytical formula is obtained for the amplitude of the phase-transition rate. On the base of this formula the influence of the initial concentration of the gas was investigated. It is shown that the presence of relatively small amount of inert gas in the bubble can considerably decrease the phase-transition rate. This is related with the mutual diffusion of the components and so called "screen" effect of the inert gas at the bubble surface. This is because the vapor component loses its ability to penetrate rapidly through the shielding gas layer on the surface of the bubble. The effect of the kinetics of phase-transition rate (accommodation coefficient) on the intensity of phase-transition rate was also studied. (c) 2007 Elsevier Ltd. All rights reserved.