In a large bowl, cream butter and sugars until light and fluffy. Beat in eggs and vanilla. Combine oats, flour, baking soda and salt; gradually add to creamed mixture and mix well. Stir in chocolate chips. Chill dough for 1 hour or until firm.
Roll dough into 1-1/2 inches balls; place on greased baking sheets. Bake at 350° for 11-13 minutes or until lightly browned. Yield: about 7 dozen.