The effect of La2O3 on the catalytic properties of PtSn/Al2O3 reforming catalysts has been investigated. On catalysts with low La2O3 content (1 wt%) FTIR CO adsorption spectra show two absorption bands at 2070 and 2122 cm(-1). At higher La2O3 content (20 wt%) the band at 2070 cm(-1) diminishes progressively until it completely disappears, while the band at 2122 cm(-1) increases and shifts to 2130 cm(-1). This band is assigned to CO adsorbed on oxidized Pt. This effect is observed on samples on which PtSn-La2O3 multiphase coexists. The presence of Pt in an oxidized state is supported by XPS since Pt2+ is present on the catalysts containing Pt/Sn and La2O3. On the other hand, XPS revealed the presence of Sn2+ and Sn degrees. For the n-heptane reaction the selectivity pattern of the PtSn/Al2O3-La catalysts shows total inhibition of the formation of benzene, high olefin content, and low n-C-7 dehydrocyclization products.