Preheat oven to 350 degrees.
Cream butter and sugars. Beat eggs into mixture one at a time. Add vanilla. Fold bananas into mixture.
Sift flour, baking powder, baking soda, and salt together. Stir into banana mixture. Fold in pecans.
Put in greased 8-1/2x4-1/2x2-1/2 loaf pan. Bake 45 minutes to 1 hour.