This randomized, crossover study compared the effects of consuming high-fiber oat and wheat cereals on postprandial metabolic profiles in healthy men. Twenty-seven subjects received oat (providing 5.7 g/day beta-glucan) or wheat (control) cereal products, in random order, incorporated into their usual diets for two weeks. Total energy and fiber (approximately 14 g/day) contents of the cereals were matched. A meal tolerance test that included the study cereal and a high-fat milkshake (1240 kcal, 105 g fat) was performed at the end of each treatment period. Postprandial insulin and glucose responses over 10 hours did not differ between treatments. Peak triglyceride concentration was lower after oat vs. wheat cereal consumption [2.3 +/- 1.2 (mean +/- standard deviation) vs. 2.9 +/- 1.3 mmol/L, p = 0.016]. Mean area under the triglyceride curve also tended to be lower (15.1 +/- 8.2 vs. 17.6 +/- 8.6 hours x mmol/L, p = 0.068). The free fatty acid area under the curve was elevated after the oat vs. the wheat products (3.64 +/- 0.91 vs. 3.38 +/- 0.98 hours x mmol/L, p = 0.018). These results suggest that high-fiber oat cereal influenced postprandial triglyceride and free fatty acid levels, which may have implications regarding cardiovascular disease risk.