This study is concerned with the experimental and numerical analysis of thermohaline natural convection in an aqueous solution, driven by melting of a block of pure ice into the liquid mixture. Experimentally, the flow structure evolution and the heat transfer characteristics are studied for a binary H2O–Na2CO3mixture in the domain of negative buoyancy ratios and for a wide range of solutal and thermal Rayleigh numbers. The observations are analyzed with the help of the classical results about cell formation in a stratified fluid due to sideways heating. The comparison with the numerical results shows that the mechanisms that define the flow structure are essentially due to thermohaline convection and not to the melting process. Finally, the fusion kinetics is analyzed, and the melting rate is correlated to the governing parameters of natural convection in the liquid. ©1996 American Institute of Physics.