Preheat oven to 350. Grease 2 medium size loaf pans.
Mix together flour, baking soda and salt.
In mixing bowl, beat butter and sugar until light and fluffy.
Add 1 egg in at a time, then add vanilla.
Add in bananas and then flour mixture until thoroughly combined.
Carefully fold blueberries into batter, pour into loaf pans.
Bake in preheated oven 30-35 minutes, or until toothpick inserted in comes out clean.
Cool on wire pans for 10 minutes, then cool thoroughly on wire racks.