Palm oil mill effluent (POME) can be utilised directly as the sole substrate in the anaerobic fermentation of acetone-butanol-ethanol (ABE) and hydrogen by Clostridium acetobutylicum NClMB13357 in a submerged batch system. Effects of sedimented POME concentration and the initial culture pH on the production of ABE/H were studied. Sedimented POME with 90% v/v (POME90) at pH 5.8 is capable of producing 4.01 g/L ABE with acetone concentration at 1.97 g/L; butanol 1.74 g/L and ethanol 0.3 g/L. The highest concentration of butanol (1.86 g/L) was produced from a culture with initial pH 6.0. The production of hydrogen gas was proportioned to the concentration of POME. The highest hydrogen gas production was at pH 5.5 (31 mL). More than 50% (v/v) of hydrogen gas was produced at different pH except pH 4.5, when only 16% (v/v) or 5 mL of hydrogen was produced.