Abstract: The objectives of the following study were to compare a recently developed low lignin- high fat oat with regular oat as an energy source for use in diets fed to growing-finishing pigs and to determine if the performance of pigs fed diets containing oat could be improved through enzyme supplementation. A total of 144 crossbred pigs (26.9?3.5 kg BW) were assigned on the basis of sex, weight and litter to one of six dietary treatments in a factorial design experiment (diet x sex). The control diet was formulated using barley and soybean meal while two experimental diets were formulated in which 40% of either normal or low lignin-high fat oat was substituted for barley. All diets were fed either with or without dietary enzyme (750 units gG of beta-glucanase and 650 units gG of xylanase). Enzyme supplementation increased dry matter (p<0.05) crude protein 1 (p<0.05) and energy (p<0.05) digestibility. Digestibility coefficients for dry matter and energy were significantly higher for the barley-based diets than for either the normal oat (p<0.05) or low lignin-high fat oat (p<0.05) diets. In contrast, digestibility coefficients for crude protein were lower for the barley-based diet than the normal fat (p<0.05) or low lignin-high fat (p<0.05) diets. For the overall experiment (26.9-111.3 kg), enzyme supplementation had no effect on growth or feed intake (p>0.05) but feed conversion was marginally improved (p<0.10). Daily gain and feed consumption for pigs fed both normal oat and low lignin-high fat oat were significantly higher than for pigs fed barley (p<0.05). Feed conversion was unaffected by the type of cereal fed (p>0.05). Barrows gained weight significantly faster (p<0.05) and had higher feed consumption (p<0.05) than gilts but had poorer feed conversion (p<0.05). Enzyme supplementation had no effect on swine carcass traits (p>0.05). Pigs fed diets based on low lignin-high fat oat had higher carcass value index (p<0.10) than pigs fed normal oat. Lean yield was lower (p<0.10) and loin fat higher (p<0.05) for pigs fed normal oat than for pigs fed the barley-based diets. Barrows had higher slaughter weights and loin fat than gilts (p<0.05) while dressing percentage, carcass value index, lean yield and loin lean were significantly lower (p<0.05). The overall results of this experiment indicate that both normal and low lignin-high fat oat can substitute for barley at levels as high as 40% of the diet without hindering pig performance. Since the average yield of oat can be equal or higher than barley with lower input costs, a re-examination of feeding recommendations regarding oat in swine rations seems warranted. There appears to be greater potential to utilize oat, regardless of fat level, in rations fed to growing-finishing pigs than is currently being achieved.