A survey of the mechanical properties of yttrium and the effects of fifteen different elemental impurities and alloying additions on its tensile strength, ductility, and hardness are described. These properties were found to be relatively insensitive to small additions of most of these elements. Factors which influence the mechanical properties of yttrium to the greatest extent are heat treatment, degree of cold working, and grain orientation. Yttrium exhibits an anisotropy of hardness as determined from single crystal studies and strain hardens extensively with a small degree of cold working. Its hardness is quite dependent also upon the thermal history of the specimen.