The present study aims to determine the chemical composition, nutritional evaluation and bioactive compounds content of oat (Avena sativa) flour and its effects on obesity complications in rats. Oat flour had 10.33, 12.45, 6.63, 3.71, 2.06 and 64.82 percent moisture, total protein, crude fat, crude fibre, ash, and carbs, respectively. Additionally, total energy (Kcal/100g), adult man's daily requirements for protein (GDR/protein) and energy (GDR/energy), and percent satisfaction of adult man's daily requirements in protein (P.S./protein) and energy (P.S./energy) were 368.75, 506.02, 786.44, 15.81, and 10.17, respectively. Furthermore, bioactive compounds content of oat flour indicated that dietary fiber (g.100g-1), β-glucans (soluble fiber) (g.100g-1), phenolics (mg gallic acid equivalent. 100 g-1), flavonoids (mg catechin equivalent. 100 g-1) and carotenoids (mg.100g-1) were 12.44, 4.46, 3.35, 2.36 and 4.97, respectively. The oat flour samples also recorded several very high biological activities which include antioxidant and radicals scavenging activities. The bioactive components content and biological effects of oat flour have played an essential role in obesity prevention and treatment efforts. As a result, the current study suggests that oat flour be included in our everyday meals and as a food supplement.