In large bowl, stir together the cake mix and sugar. Make a well in the center, and pour in eggs, cream cheese, oil and vanilla. Beat on low speed until blended. Scrape bowl, and beat 4 minutes on medium speed. Stir in the blueberries.
Pour into prepared bundt pan.
Bake at 325 degrees for 40 -45 minutes or until a toothpick inserted comes out clean. Let cool in pan for 30 minutes then turn out onto rack to cool completely.