house wastewaters contain high levels of organic matter and otherrnpollutants. These pollutants can cause undesirable effect on the ecosystem and publicrnhealth. In Ethiopia most of slaughter house industries discharge their effluent withoutrnany treatment to the nearby rivers. This creates a serious effect on aquatic biota andrnsurrounding environment. To minimize the effects these pollutants must be reduced tornthe acceptable limits during wastewater treatment. Biological treatment method isrncost effective and environmentally friendly than physico-chemical treatment method.rnThe objective of this study was to evaluate the treatability and biogas productionrnpotential of slaughterhouses wastewater in a laboratory scale anaerobic sequencingrnbatch reactors. To achieve this objective, the biogas production potential and removalrnefficiencies of COD, BOD5, TKN, NH4rn+-N, NO3rn--N, SO4rn-2 and PO4rn3- were investigatedrnat mesophilic and thermophilic temperature with three different OLRs of 2.11, 1.12rnand 0.53kg COD/ (m3.d) and HRT of 3 and 5 days. The maximum volume of biogas inrn5days HRT and thermophilic temperature for (T-1 to T-3) 0.0030, 0.0045 and 0.0063rnm3/ kg COD) with methane content 57.4%, 65.2%, 67.5% ,respectively was obtainedrnafter steady stable state condition was obtained. The removal efficiency of COD,rnBOD5,TKN, NH4rn+-N, NO3rn--N, SO4rn-2 and PO4rn3-, total coli forms and fecal coli forms ofrnall treatments were 79.9%, 85.6.%, 48.5%, 54.8%, 69.5%, 79.6%, 78.2%, 97%, 95%rnrespectively. The content of major plant nutrients in the treatments after anaerobicrntreatment were 0.08+0.03% total nitrogen, 0.06+0.02% of available phosphorus andrn0.10+0.05% of available potassium. Thus, anaerobic Sequencing batch reactor wasrnfound to be efficient for production of biogas and for the removal of organic matterrnand pollutants in slaughter house wastewater.rnKey words/Phrases: slaughter house wastewater, biogas, slurry, anaerobic sequentialrnbatch reactor, macro nutrient.