Preheat the oven to 350 degrees. Grease a 9?x5? loaf pan.
Mix together the dry ingredients. With an electric mixer, cream the butter with the sugar, then slowly beat in the eggs, bananas and vanilla.
Slowly add the dry ingredients to the wet ingredients and beat just until combined, being sure to scrape down the edges of the bowl a few times. Gently fold in the chocolate chips.
Pour the batter into the loaf pan and bake for 45 to 60 minutes, until nicely browned. A toothpick inserted into the center of the bread will come out fairly clean when it is done, but because of the bananas this bread will remain moister than most. Cool on a rack for 15 minutes before removing from the pan.