Résumé : The paper deals with the numerical investigation of the influence of static and vibrational acceleration on the measurement of diffusion and Soret coefficients in binary mixtures, in low gravity conditions. In space experiments, liquids with inhomogeneous composition are prepared by Soret diffusion under an imposed temperature gradient. So, the process under consideration consists of two stages. First, a mixture is maintained at a fixed temperature gradient which results in a thermal diffusion separation of the components - the value of the Soret coefficient is calculated from the steady-state characteristics. The second stage corresponds to the diffusion process under isothermal external conditions and permits calculation of the diffusion coefficient. The modeling is made for a rectangular cavity subjected to static acceleration (normal gravity) and/or vibrational accelerations with different levels and orientations. In the last cases, the vibration period is assumed to be small in comparison with hydrodynamical time scales and the product of their amplitude; in addition, the Boussinesq parameter is small compared to the cavity size. This allows to decompose the processes into slowly varying (time-average) and quickly oscillating (pulsational) components and to implement appropriate equations for the vibrational convection. The influence of acceleration level on transient process and steady-state characteristics is identified for various binary mixtures that are candidates for space experiments. © 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.