Sago starch processing effluent (SSPE) is an ideal bio-resource that can be utilised as a substrate for fermentative reactions due to its relatively high organic content. Annually in Malaysia, about 2.5 million tonnes of effluent are generated from the processing of sago starch. In this study, the potential use of SSPE as a substrate for fermentative hydrogen production was confirmed under all the experimental conditions studied. The maximum hydrogen production and volumetric hydrogen production rate were 575 mL H-2/L SSPE and 57.54 mL H-2/hr.L SSPE, respectively, from cultures with an initial pH of 7 and substrate concentration of 11 g soluble carbohydrate/L SSPE. The final soluble metabolites were comprised mainly of acetate (24-43%), butyrate (4-20%), propionate (1-7%) and ethanol (44-66%), suggesting an acetic acid-ethanol type fermentation pathway. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.