Biomass steam gasification with in-situ carbon dioxide capture using CaO exhibits good prospects for the production of hydrogen rich gas. The present work focuses on the process modeling for hydrogen production from oil palm empty fruit bunch (EFB) using MATLAB for parametric study. The model incorporates the reaction kinetics calculations of the steam gasification of EFB (C3.4H4.1O3.3) with in-situ CO2 capture, as well as mass and energy balances calculations. The developed model is used to investigate the effect of temperature and steam/biomass ratio on the hydrogen purity, yield and efficiency. Based on the results, hydrogen purity of more than 76.1 vol.% can be achieved. The maximum hydrogen yield predicted at the outlet of the gasifier is 102.6 g/kg of EFB. It is found that increment in temperature and steam/biomass ratio promotes hydrogen production. However, it is also predicted that the efficiency decreases when using more steam. Due to the still on-going empirical work, the results are compared with published literatures on different systems. The comparison shows that the results are in agreement to some extent due to the different basis. (C) 2011 Elsevier B.V. All rights reserved.