With increasing the greenhouse gases (GHGs) gas emissions into the atmosphere and the possible consequence for the global climate change, there has been a growing interest in develop efficacy management strategies of reducing anthropogenic GHGs emissions. Municipal solid waste (MSW) management plays an important role in the GHGs emission. The contribution of the landfilled MSW to GHGs it was reported to be of 5% of the total GHGs emitted and of the 13% of the methane from anthropogenic fonts (USEPA, 2003; IPCC, 2006). The compute of the total GHG emissions is determined quantifying the GHG gases from all human activity as credits and debits. Debits are the GHG emitted in the atmosphere; on the other hand, the credits are the storage on C in stable forms (C-based systems) (IPCC, 2006; Brown et al., 2008). Because the production of CH4 vs CO2 during MSW degradation depends by aerobic vs anaerobic conditions, the possibility to manage MSW organic fraction by aerobic biological process, i.e. composting and mechanical biological treatment, avoiding methane production in landfill, reduce GHGs emission due to MSW management. The potential reduction of the methane emission and the possibility to store C in landfill and soil under recalcitrant forms, is extensively discussed in this chapter, reporting both literature and new data