A series of materials containing 1.7 wt% Pt and with Pt/Sn atomic ratios varying from 2.25 to 0.6 were prepared using NaY support. The method used to form PtSn bimetallic is based on the reaction of tetramethyltin with hydrogen covering performed Pt particles. Different techniques such as H-2 chemisorption, CO chemisorption, IR spectroscopy, TEM and STEM-EDX analysis, and XPS were used to characterize these materials. It appears that H, and CO chemisorption are depressed with the addition of tin and that part of the tin is alloyed with Pt to form a bimetallic. The bimetallics so formed are rather heterogeneous; neither CO chemisorption and IR spectroscopy nor XPS gives clear evidence of a possible change in the electronic properties of Pt with the addition of tin.