The aim of this paper is to review promising pre-treatment technologies which have greatly improved the production of biogas. The global need for alternative energy source is rapidly growing today. Biogas has many advantages compared to other biofuels. It can be produced from lignocellulosic materials. The lignocellulosic biomass is attractive as feedstock for biogas production because of its low cost, great abundance and sustainable supply. Especially, utilisation cycles and energy production based on raw biomass have near-zero greenhouse gas emissions on a life-cycle basis. Lignocelluloses are composed of cellulose, hemicellulose, lignin and several inorganic materials. This type of biomass is not fully biodegraded in methane fermentation process on industrial scale due to their complex physical and chemical structure, which results in lower energy recovery in terms of methane yield. The biodegradability of lignocellulosic waste can be increased by a pre-treatment. Recent findings have shown that pre-treatment can improve biogas yields to higher than 90% of the theoretical yield for biomass such as wood, grasses, and corn.