The kinetics of batch anaerobic hydrogen production by mixed anaerobic cultures was systemically investigated in this study. Unstructured models were used to describe the substrate utilization, biomass growth and product formation in the hydrogen production process. The relationship between the substrate, biomass and products were also evaluated. Experimental results show that the Michaelis-Menten equation, Logistic model and modified Gompertz equation all could be adopted to respectively describe the kinetics of substrate utilization, biomass growth and product formation. Furthermore, the relationship between the acidogenic products and biomass was simulated by Luedeking-Piret model very well. The experimental results suggest that the formation of hydrogen and the main aqueous products, i.e., butyrate and acetate, was all growth-associated. (c) 2005 Elsevier Ltd. All rights reserved.