The aim of this work was to study the treatment of strong beet sugar wastewater by an upXow anaerobic Wxed bed (UAFB) at pilot plant scale. Three Wxed bed bioreactors (each 60 L) were Wlled with standard industrial packing, inoculated with anaerobic culture (chicken manure, cow manure, anaerobic sludge digested from domestic wastewater) and operated at 32–34 °C with 20 h hydraulic retention time (HRT) and inXuent COD ranging between 2000–8000mg/L. Under these conditions the maximum eYciency of organic content reduction in the reactor ranged from 75% to 93%. The reactor Wlled with standard pall rings made of polypropylene with an eVective surface area of 206m2/m3 performed best in comparison to the reactor Wlled with cut polyethylene pipe 134m2/m3 and reactor Wlled with PVC packing (50m2/m3). There was 2–7% decrease in eYciency with PE while it was 10–16% in case of PVC when compared to standard pall rings. The study provided a very good basis for comparing the eVect of packing in reduction eYciency of the system.