Oxidation is the primary cause of aging in asphalt pavements. The use of an antioxidant as a performance enhancer in an asphalt could delay aging, thus increasing the life of an asphalt pavement. Lignin is a highly-available, well-studied antioxidant. The use of lignin from ethanol production could provide benefit to asphalt pavements while also giving more value to the co-products. Lignin-containing co-products were each combined with four asphalt binders separately in varying amounts to determine the optimum amount of co-product that would provide the greatest benefit to the asphalt binders. The data indicates a stiffening effect of the binder. The more co-product added, the greater the stiffening. Binder stiffening benefits the high temperature properties, while the low temperature binder properties are negatively affected. However, the low temperature effects are small, and in many cases not significant. The co-products have an overall effect of widening the temperature range of the binders.