A DSC experimental study of the dissolution kinetics of β precipitates in an Al Mg Si alloy has been carried out in order to test the validity of a recent particle dissolution model [F.J. Vermolen, K. Vuik, S. van der Zwaag, Mater. Sci. Eng. A246 (1998) 93-103; F.J. Vermolen, K. Vuik, S. van der Zwaag, Mater. Sci. Eng. A254 (1998) 13-32; F.J. Vermolen, Ph.D Thesis, Delft University, Press, The Netherlands]. The results demonstrate that the model is successful in simulating particle dissolution during linear heating. The concentrations of both alloying elements at the particle-matrix interface during particle dissolution are decided by both the solubility product and the diffusion coefficients. The existence of a size distribution of particles was found to have a significant effect on the dissolution kinetics and therefore should be included in any model if an accurate prediction of the dissolution kinetics is to be achieved.