Food habits of northern pike (Esox lucius) were documented in Lake Thompson, a shallow, windswept, eutrophic lake in eastern South Dakota. The primary food items, assessed with the Relative Importance Index, eaten by northern pike were common carp (Cyprinus carpio), crappies (Pomoxisspp.), and fathead minnows (Pimephales promelas). Common carp were eaten in midsummer and winter. Crappies were eaten primarily in the winter. Fathead minnows were an important food source throughout the year.