Display omitted •A detailed study of the composition effect on structural and textural properties in CexPr1-xO2-δ (0 < x < 1) was conducted.•The calcination temperature on the catalysts’ synthesis was explored, along with their catalytic activity for soot combustion.•Ceria-praseodymia mixed oxides show improved catalytic activities for soot combustion with respect to ceria.•Ce0.5Pr0.5O2-δ-500 exhibits the highest catalytic activity in soot combustion under NOx/O2 atmosphere, among those studied. The effect of Ce/Pr ratio on ceria-praseodymia on structural and surface properties is studied. The catalytic activity towards soot combustion under NOx/O2 and O2/N2 atmospheres is also evaluated, together with the NO oxidation activity to NO2. CexPr1-xO2-δ compositions (x = 0.8, 0.5 and 0.2) have been prepared along with ceria and praseodymia. Catalysts were prepared by co-precipitation. The Ce0.5Pr0.5O2-δ composition, was also prepared by nitrate calcination. Ceria-praseodymia mixed oxides yield reduction profiles shifted to lower temperatures, higher NO oxidation activities to NO2 and improved catalytic activities for soot combustion with respect to pure ceria. Ce0.5Pr0.5O2-δ was the most active one. Under NOx/O2, it has greater soot combustion activity if it is prepared by nitrate calcination. However, under O2/N2, the co-precipitation method is more favorable because of the better dopant insertion achieved in the ceria lattice, which seems to lead better oxygen mobility on the surface and in the bulk oxide.