Differently prepared Ni and Pt containing HMFI, HMOR and HBEA zeolites for the hydroconversion of n-nonane were studied. The objective was to investigate the role of acid and metal site density, the influence of the kind of the metal, and the pore dimension on the activity and selectivity. The reaction rate increased linearly with the number of acid sites, whereas the isomerization selectivity remained constant. The reaction rate and the selectivity to isomerization increased first with increasing concentration of metal sites and then remained constant up to 2% Pt content. The reaction rate ran through a maximum when Ni was used as metal component. To reach the same activity approximately 1.1 wt.% Pt and 10 wt.% Ni were necessary. The selectivity to isomers was the highest over the BEA samples, whereas the highest activity was found for the MFI samples.