Gold nanoparticle catalysts have attracted much attention due to their catalytic efficiency under mild conditions. We report here the synthesis of a series of shapes of gold nanocrystals by simple reduction of HAuCl4⋅3H2O and application them as the catalysts for multicomponent Biginelli reaction. Amongst these, unsupported gold nanorods show the best catalytic activity. Its efficiency allows one‐pot synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones to proceed in high yield under mild conditions.