The invention provides a rubber composition for golf balls which includes a base rubber, (B) a metal salt of an unsaturated carboxylic acid and/or an unsaturated carboxylic acid and zinc oxide, (C) an organic peroxide, and (D) from 0.1 to 5 parts by weight of a metal salt of a thiol having the general formula (R—S)nM (wherein R is a monovalent hydrocarbon group having from 12 to 30 carbons, exclusive of aromatic groups; n is an integer such as 1, 2 or 3; and M is a metal) per 100 parts by weight of the base rubber. The golf ball-forming rubber composition of the invention is suitable for pressure molding and has an excellent productivity because it does not lower the rate of vulcanization. The golf ball of the invention, which is formed using the composition, is endowed with an excellent rebound.