The principle of lattice-Boltzmann techniques is recalled and some of the difficulties to simulate convective flows are discussed. It is then proposed to use a hybrid scheme with lattice-Boltzmann for fluid velocity variables and finite-difference for the temperature. Convergence studies are presented for particular cases. Some results for two and three-dimensional situations are given. Possible extensions of hybrid schemes are discussed. (C) 2003 Elsevier Ltd. All rights reserved.