The anaerobic treatment of raw vinasse in a combined system consisting in two methanogenic reactors, up-flow anaerobic sludge blanket (UASB) + anaerobic packed bed reactors (APBR), was evaluated. The organic loading rate (OLR) was varied, and the best condition for the combined system was 12.5 kg COD m(-3)day(-1) with averages of 0.289 m(3) CH4 kg COD r(-1)for the UASB reactor and 4.4 kg COD m(-3)day(-1) with 0.207 m(3) CH4 kg COD r(-1) for APBR. The OLR played a major role in the emission of H2S conducting to relatively stable quality of biogas emitted from the APBR, with H2S concentrations < 10 mg L-1. The importance of the sulphate to COD ratio was demonstrated as a result of the low biogas quality recorded at the lowest ratio. It was possible to develop a proper anaerobic digestion of raw vinasse through the combined system with COD removal efficiency of 86.7% and higher CH4 and a lower H2S content in biogas.