Coal during its carbonization process produces a gas, which, mainly formed by methane, can be used. The use of CBM (Coal bed methane) as an energetic resource is not much known in Spain. This work is the first step to enhance the development of this resource in Castilla y León Guardo-Barruelo basin. A review of the state of the art is introduced, taking into account all the factors that can influence in the development of a CBM project. Then CBM resources have been quantified for Guardo-Barruelo basin accurately for every coal bed. After that, technical feasibility has been used to evaluate total amount of gas that can be recovered.