The anaerobic treatability of young municipal leachate from Istanbul's sanitary landfill was investigated using a laboratory scale UASBR. In the first part of this study, the reactor was operated with a feed COD concentration of 10250 mg.l(-1) and a retention time of 2.84 days, giving an organic loading rate 3.7 kg COD.m(-3).d(-1). Total COD removal was around 94% under that condition. In the second part of the study, feed COD's were varied from 9000 to 25000 mg.l(-1). Whereas retention times ranged from 1.7 to 2.35 days and COD removal ranged from 92 to 94%.