The present invention provides a golf ball with excellent abrasion-resistance, durability and resilience having an ionomer resin cover therein. The ionomer composition for the golf ball of the invention comprises a reaction product obtained by reacting a telechelic copolymer having functional groups introduced in both terminals of a binary copolymer formed by copolymerizing an olefin monomer having 2 to 8 carbon atoms and an unsaturated carboxylic acid having 2 to 18 carbon atoms, and/or a ternary copolymer formed by copolymerizing an olefin monomer having 2 to 8 carbon atoms, an unsaturated carboxylic acid having 2 to 18 carbon atoms and an unsaturated carboxylic acid ester with a hydroxyl group-containing compound or an isocyanate group-containing compound, wherein at least 10 mole % of a carboxylic group in said reaction product is neutralized with an inorganic metal.