Supported PdAg bimetallic catalysts were evaluated for the selective hydrogenation of acetylene in the presence of ethylene. The effects of different zeolite structures and cations were investigated using flow reactor studies, with K+-beta-zeolite supported PdAg showing the lowest activity but highest selectivity comparing to the gamma-Al2O3 support and other alkaline metal exchanged beta-zeolite supports. The K+ promoter effect on gamma-Al2O3 was also tested, which showed that adding K+ to gamma-Al2O3 increased activity and selectivity. Bimetallic catalysts consisting of Pd and a Group IB metal were also compared. It was found that the PdAg bimetallic catalyst had similar activity but better selectivity comparing to PdCu, while the PdAu catalyst showed the highest activity but lowest selectivity.