Energetics will continue to be of great importance to the swine industry because energy contributes a significant expense to feed which contributes more than 60% of pig production costs. Changes in the corn milling industry are improving the quality and increasing the variety of co-products that can be fed to pigs. Accurate energy values must be established on these new co-products as they are developed to provide nutritionists more options in generating balanced diets. The twenty co-products evaluated in this study had unique nutrient profiles and resulted in a wide range of organic matter digestibility and apparent metabolizable energy values. The in vitro organic matter (OM) digestibility ranged from 33.3 to 93.5% for corn bran and dried solubles, while metabolizable energy (ME) ranged from 2,334 to 8,755 kcal/kg for corn gluten feed and corn oil, respectively. Although in vitro OM digestibility was correlated to in vivo ME (r = 0.62, P < 0.01), it did not improve the prediction of ME from ingredient analysis. Stepwise regression resulted in the equation: ME, kcal/kg = (0.949 × gross energy) – (32.238 × total dietary fiber) – (40.175 × ash) (r2 = 0.95, SE = 306, P < 0.01), thereby providing a reliable estimate of ME in corn co-products commonly fed to growing swine. For further information, contact Dr. Brian Kerr, USDA-ARS, Ames, IA, by phone (515-294-0224) or email ([email protected]).