Cardiovascular disease is the primary cause of death in the United States among both men and women, and diabetes is one of the fastest growing chronic diseases worldwide. Yet, both conditions are considered preventable with lifestyle change. Epidemiologic studies have demonstrated that increased dietary fiber intake, specifically soluble fiber, can help prevent both cardiovascular disease and diabetes and is recommended by both the American Heart Association and American Diabetes Association. However, it is unknown whether all soluble fibers have equivalent effects on cardiovascular disease and diabetic risk. This article discusses some of the seminal epidemiologic studies relating to dietary fibers and cardiovascular disease and diabetic risk and focuses on the relationship between beta-glucan from barley sources and its effects on blood lipids, glucose, and insulin, as well as possible mechanisms of action.