High energy prices and an established awareness of the anthropogenic origin of global warming are stimulating markets and policymakers to move toward a much higher utilization of biomass fuels for energy conversion. In order to develop efficient processes, though, much research is still needed to characterize the behavior of such alternative fuels. In this paper the pyrolysis of some agro-residues, abundant in Europe, was studied in a TG-FTIR setup. In order to remove from the samples the alkali metals and Cl which are detrimental for process operation, causing slagging, fouling, and loss of fluidization, a water leaching pretreatment was applied to all the samples. The thermogravimetric curve of wheat straw showed a singular peak at 324 °C and a residue of 21.6 wt % ar. The leaching pretreatment increased the temperature of reaction up to 355 °C and the weight loss to 83.3 wt % ar. The olive residue sample also showed an increase in reacting temperature and volatile release. The peach sample, probably du...