Although agricultural wastes such as corn cob could be employed as substrates for biogas production, their lignocellulosic nature entails difficulties for their use. For this reason, a pretreatment of the biomass is recommended. Considering that there is limited information about the effects of extrusion as pretreatment on biogas production from biomass, this pretreatment alone or in combination with alkali and/or with the enzymatic hydrolysis was evaluated to improve the production of methane by anaerobic digestion of corn cob. The lignocellulosic composition, methane yields and biogas composition of the corn cob before and after pretreatments were compared. Among all the pretreatments studied, the sequential alkali extrusion and enzymatic hydrolysis (A+FE+H) pretreatment accomplished the major improvement with an increase of the methane volume produced of 22.3% in regards to the anaerobic digestion of the raw corn cob.