Hydroisomerization of n-pentane over platinum promoted acid zeolites was studied. The effect of structure and strength of acid sites of the support was investigated on the reaction carried out under atmospheric pressure at 300 degrees C. In order to accomplish the above purpose, some zeolitic catalytic systems were studied, which have the same structure but different acidity and with similar acidity but different structure. (C) 2009 Elsevier B.V. All rights reserved.