In order to describe the transport behavior of particles in continuously operated horizontal fluidized beds residence time distribution experiments were conducted in a pilot-scale and lab-scale plant. The Bodenstein number, which is defined as the dimensionless ratio of convective to dispersive particle transport is used as a measure for axial dispersion in horizontal fluidized beds. Significant process parameters, such as superficial gas velocity, particle mass flow rate, particle size and apparatus dimensions were varied, and their influence was investigated. Furthermore, experimental data from literature was taken into account and analyzed. From the observed trends a new dimensionless correlation was derived in order to predict the Bodenstein number. It is shown that predictions of the new correlation fit well to the experimentally determined Bodenstein numbers of this work as well as from literature. (C) 2016 Elsevier B.V. All rights reserved.