<P><B>Abstract</B></P> <P>A 4m<SUP>3</SUP> pilot-scale baffled continuous-flow photoreactor with four sequential chambers (#1–#4) was established and tested to evaluate its photo-fermentative hydrogen production from wastewater that contains (10g/L glucose using a functional consortium at 30°C, under light with an intensity of 3000±200lux with a hydraulic retention time (HRT) of 24–72h. The hydrogen production rate and the broth characteristics varied significantly in the flow direction. The hydrogen production rate was highest in chamber #1, and lower in chambers #2–#4 at an HRT of 72h, while the peak production rate shifted to the latter chambers as the HRT was shortened. The overall H<SUB>2</SUB> production rate increased as HRT decreased, but was not consistent with the predictions that were based on the complete-mixing assumption.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A 4m<SUP>3</SUP> pilot-scale baffled continuous-flow photoreactor was established. </LI> <LI> Photo-H2 was produced from glucose at 30°C, 3000lux and 24–72h HRT. </LI> <LI> Significant inhomogeneity in medium and performance was noted. </LI> <LI> Overall H<SUB>2</SUB> production rate was increased with decreasing HRT. </LI> </UL> </P>