Résumé : The paper presents numerical simulations of the Marangoni-Bénard convection in a real symmetric three-layer system. The temperature gradient is directed along the interfaces. Nonlinear regimes of steady and oscillatory convective flows are investigated by means of the finite-difference method. Transitions between the motions with different spatial structures are studied. To cite this article: V. Shevtsova et al., C. R. Mecanique 333 (2005). © 2005 Académie des sciences. Published by Elsevier SAS. All rights reserved.