Landfill leachate contains both larger fractions of higher molecular weight organic materials and heavy metals. The study investigated the effect of coagulation as pretreatment during anaerobic treatment process on stabilized landfill leachate. Anaerobic studies were done on the raw stabilized leachate and on the pretreated leachate, where coagulation was used as a pre-treatment process for leachate. Landfill leachate samples were collected from India's largest and oldest landfill i.e. Deonar landfill, Mumbai. The leachate was characterized by high TS (10,910 mg/l), COD (2,300 mg/l), BOD (238 mg/l), TOC (716 mg/l) and low BOD/COD ratio (0.10). FeCl3 and PACl were used as coagulants for the coagulation process. The highest removal efficiency obtained by FeCl3 and PACT for COD was 53 and 59%, respectively. The highest removals of TOC were 52 and 57% by FeCl3 and PACl, respectively. The optimum pH and dose for FeCl3 was found to be 8 and 7 g/l, respectively. The best pH and dose for PACT was found to be 6 and 10 g/l, respectively. Anaerobic batch reactor treatment was applied as secondary treatment on pre-treated leachate and also on raw leachate. Anaerobic batch experiment was performed for batch time 72 h with solids retention time of 10 days. When anaerobic batch treatment was done on raw leachate, it showed constant 35% TOC and 38% COD removal after 40 h. In the case of anaerobic batch experiment after coagulation, the overall TOC and COD removal was found to be 70 and 72%, respectively.