This paper presents an experimental investigation on natural convection in a molten metal subject to a uniform magnetic field. The working fluid is molten gallium, which is contained in a rectangular box with the two opposite vertical walls held at different temperatures. The imposed magnetic fields are parallel to the temperature gradient. Both the temperature and velocity fields are measured with and without an imposed magnetic field. Numerical simulations of convective flows in the system are also performed using the numerical model developed in a previous study. Good agreement exists between the measured and computed results for the conditions studied. Results show that natural convection is suppressed with an imposed magnetic field and the magnetic damping effect increases with an increase in the applied field strength. (c) 2006 Published by Elsevier Ltd.