Methods for making golf balls having a cover made from polyurea and polyurethane compositions are provided. The methods for making the polyurea and polyurethane composition involve preparing an amine-terminated or hydroxyl-terminated first prepolymer by reacting a first isocyanate compound with a stoichiometric excess of polyamine or polyol (depending on the type of prepolymer desired). The first prepolymer is then reacted with a stoichiometric excess of a second isocyanate compound to form an isocyanate-terminated second prepolymer. The second prepolymer is then reacted with a chain extender.