Line a 9x9 inch baking pan with aluminum foil and set aside.
Add the chocolate chips and condensed milk to a large microwave safe bowl. Microwave in 30 second intervals, mixing until smooth.
Mix in the vanilla extract, then transfer to the prepared baking pan.
Refrigerate for at least 3 hours, or until set.
Cut the fudge while still cold, and store in an airtight container.