Controlled growth of ZnSe and ZnCdSe nanowires is demonstrated by molecular beam epitaxy using Au or Ag catalyst films in the temperature range 400–550 C. The highest density of small-diameter (10 nm), highly-crystalline ZnSe nanowires is achieved by using Au at 400 C. Direct growth onto transmission electron microscope grids clearly indicates a tip-growth regime. Pre-patterning of the catalyst film allows highly selective ZnSe deposition as probed by photoluminescence and Raman spectroscopy. In similar conditions, the addition of Cd vapour in the MBE reactor allows the synthesis of ZnCdSe ternary nanowires.