In large mixing bowl, combine butter, sugars, eggs and vanilla. Using an electric mixer on medium speed, beat until creamed, scraping bowl often.
Reduce mixer to low; slowly add flour, baking soda and salt until well combined, scraping bowl often. Add bananas and chocolate chips, continue mixing until well combined.
Transfer to a greased 13x9-inch baking pan. Bake in a preheated 350°F oven 30-35 minutes or until a knife inserted in the center comes out clean. Cool and cut into bars.