In a large bowl with an electric mixer on medium speed, combine peanut butter, sugar and butter.
Beat until smooth.
Scoop out spoonfuls and roll into 1-inch balls.
Arrange on baking sheet and refrigerate 30 minutes.
Line another baking sheet with waxed paper.
Place chocolate chips in top of double boiler.
Melt over simmering water, stirring until smooth.
Using wooden toothpicks, dip balls into chocolate to coat completely, letting excess drip back into pan.
Set balls on prepared sheet.
Store in refrigerator.