Preheat oven to 350 degrees Fahrenheit.
In a large bowl, cream together butter, peanut butter, white sugar, and brown sugar until smooth.
Beat in eggs one at a time, then stir in vanilla.
Combine flour, baking soda, and salt; gradually stir into peanut butter mixture.
Roll dough into 1-inch balls and place on ungreased cookie sheets.
Bake for 10 to 12 minutes in the preheated oven, or until golden. Cool cookies on wire racks.