Place thawed blueberries into a blender and purée.

Pour puréed blueberries, sugar, water, and Karo syrup into a small sauce pan.

While stirring, bring mixture to a boil.

Continue boiling and stirring until sugar has dissolved and mixture has thickened into a syrup consistency.

Remove from heat and serve or you may want to slowly pour syrup through a metal strainer with very small holes. This will make the syrup more smooth. However, this is not necessary-it's just an option.

Serve and Enjoy!