Intensive vegetable production in greenhouse systems has been largely developed in southeast Spain in the past 40 years, thus the elimination of tonnage amounts of by-products inherent to this economic activity constitutes a major problem to solve. To discern the suitability for biogas production of the different by-products generated, a study about their proximate composition was carried out in fresh and ensiled material. The output of the analyses indicates a chemical composition similar to medium-high quality forages, since all exhibited high protein and digestible fiber content, and a low amount of lignin, showing the applied model an optimal potential for methane production.