Sludge from a Moroccan dairy industry, constitute a source of organic matter ranging between 74 to 95%. Assessment of methane production in batch reactor at 38°C in laboratory scale according to three dilutions showed promising results. The co-digestion gave 11 times more methane production for BS and 3 times for PCS given by the mixture M₃ at dilution 4 compared to mono-digestion that gave respectively 5.6 and 20.79mlCH_4STP/gVS in substrate without dilution. Significant synergy between BS, PW and LDP was observed. In contrast, PCS showed a low synergy with these co-substrates. The TS and VS abatement exceeds 83% and 86% respectively for M₃.