Computational fluid dynamic simulations were performed using the commercial program Fluent in order to study the hydrogen concentration decay along the centerline of free horizontal subsonic jets. The hydrogen jets were assumed to be steady and turbulent. To explore the buoyancy effect on the hydrogen dispersion processes, the Froude numbers were varied from 250 to 1000. Zero gravity jets were also simulated and analyzed in order to determine the jet momentum dominated limit. Classical similarity analysis was performed and our results were compared to the results of vertical axisymmetric free jets from the literature. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.