The Lafayette B. Mendel House is an historic Italianate house at 18 Trumbull Street in New Haven, Connecticut. This building, designed by New Haven architect Henry Austin, was the home of Yale University physiology professor, Lafayette Benedict Mendel (1872-1935) from 1900 – 1924. It was declared a National Historic Landmark in 1976 for its association with Mendel, who discovered vitamins A and B, and greatly expanded knowledge of nutrition and food-related biochemistry. The building now houses a law firm.