Laboratory scale studies were conducted in an up-flow anoxic bioreactor using synthetic fertilizer wastewater for ascertaining the denitrification efficiency. The performance of the reactor was compared using ethanol and topioca starch as the carbon source. The initial NO3-N concentrations (50-250 mg/L) and hydraulic retention time (HRT, 12-24 h) were varied to evaluate the COD and NO3-N removal. The results from this study shows that ethanol gave very good denitrification efficiency (78-98%) compared to topioca starch (68-96%). © Spring 2007, IRSEN, CEERS, IAU.