The intermetallic alloy series CePd3-xAux (0 less-than-or-equal-to x less-than-or-equal-to 1) has been prepared from its constituent elements by carbon arc melting and employed as catalysts for the hydrogenation of buta-1,3-diene at 1 bar (101.5 kPa) total pressure in the temperature range 50-120-degrees-C. Selectivities for butene formation and initial butene distributions were very similar to those measured for CePd3 and Pd-rich CePd3-xPdx alloys. Activity measurements showed that CePd2Au, was about three times more active than CePd3 despite having a surface which was shown by Auger electron spectroscopy (AES) to be deficient in Pd compared with the bulk and also compared with CePd3. Although a relationship appears to exist between catalyst activity and bulk electronic properties it can be only fortuitous and the surface electronic structure must be the important factor especially in view of the palladium-deficient surface.