Steady state simulation model for gasification has been developed using Aspen Plus. The model can be used as a predictive tool for optimization of the gasifier performance. The Gasifier has been modeled in three stages. In first stage moisture content of biomass feed is reduced. In second stage biomass is decomposed into its elements by specifying yield distribution. In third stage gasification reactions have been modeled using Gibbs free energy minimization approach. The simulation results are compared with the experimental results obtained through hybrid biomass gasifier. In the simulation study, the operating parameters like Temperature, Equivalence Ratio (ER), Biomass Moisture Content and Steam Injection have been varied over wide range and the effect of these parameters on syngas composition, High Heating Value (HHV) and Cold Gas Efficiency (CGE) has been investigated. Temperature increases the production of CO and H(2). Increasing ER decreases the production of CO and H(2) which decreases the CGE. Biomass moisture content is an important parameter affecting the heating value of the gas. Steam injection favors hydrogen production. The performance of the simulated gasifier has been compared using experimental data for Municipal Solid Waste (MSW), Food Waste (FW) and Poultry Waste (PW). (C) 2011 Elsevier Ltd. All rights reserved.