In the present study, two-stage H(2) and CH(4) production was compared with one-stage CH(4) production from maize subjected to water extraction and acid (HCl) treatment. In addition, the effect of duration (2 and 14 days) of the first-stage H(2) process on the H(2) yields and subsequent CH(4) yields from the second-stage was also investigated. Results showed that the average H(2) yields from untreated maize were 5.6 and 9.9 mVg volatile solids added (VS(added)) after 2 and 14 days, respectively. On the other hand, H(2) yields from waterextracted and HCl-treated maize were 18.0 and 20.5 ml/gVSadded (14 d), respectively. On comparison to one-stage CH(4) assays, the average increase in CH(4) yields from two-stage assays with 2 d H(2) stage were 7, 9 and 27% for untreated, water-extracted and HCl-treated maize, respectively. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.