Abstract: The present invention provides a method for treatment of lignocellulosic organic waste or biomass, by which the carbohydrates are rendered more available for subsequent hydrolysis, e.g. by means of addition of enzymes or direct fermentation to one or more desired products. The invention more specifically relates to a method comprising a combination of the following process steps: thermal hydrolysis, wet oxidation and wet explosion. The method according to the present invention can operate with undivided or only poorly divided substrate having a high dry matter concentration.