A new relationship for the prediction of minimum fluidization velocity is proposed. It has been made a comprehensive critical review, concluding that in order to apply, some of these correlations additional experimental data is required, such as bed voidage and shape factors. It is found a strong dependency of the physical and chemical properties of the particle surface on the minimum fluidization velocity. This influence of the nature of the particle surface allows that empirical equations are applicable in specific cases, but cannot be generalized. The original equation presented in this paper allows the predicting minimum fluidization velocity in a very simple way without the need of experimental determination of bed voidages and shape factors. The new correlation was tested using 189 measurements reported in the literature on about 90 different materials. The results shown that the new correlation is in very well agreement with the experimental data. (C) 2004 Elsevier B.V. All rights reserved.