In the present study, the pulsed laser ablation in liquid technique was used to produce palladium nanoparticles in acetone and in water. The composition, morphology and oxidation state of the obtained nanoparticles have been characterized by HR-TEM, XPS and XRD techniques. The results evidence that the nature of the solvent influences the physical-chemical properties of the products. In acetone non-aggregate metallic nanoparticles have been obtained, while in water the oxidation of the particles surface is present, as showed by the XPS analysis. Moreover, the particles obtained in water are aggregated and the coalescence effect is evident. The different size distributions of nanoparticles obtained in the two liquids have been interpreted considering the different cavitation bubble dynamics.