Platinum nanoparticles supported on Al-MCM-48 materials have been prepared. The resultant catalysts have been characterized by means of XRD, N2 physisorption experiments, scanning electron microscopy (SEM), transmission electron microscopy (TEM), temperature-programmed reduction (TPR), and diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS). The activity of these nanoparticles has been tested in relation to the hydroisomerisation of n-octane. The catalytic activities were typically 50 %, with selectivities in the isomerisation process in excess of 70 %, favouring the formation of the 3-methylheptane isomer with respect to the 2- and 4-methylheptanes.