New legislation from the California Air Resources Board and at the Federal level has made the fuel and fuel/alcohol permeation rates of rubber and plastics increasingly important to the automotive engineer. This presentation documents the permeation rates of standard fuel handling elastomers such as NBR, HNBR, and fluorosilicone and compares them to fluoroelastomers, fluoroplastics, and nylon 12. All these materials are used in fuel systems applications such as fuel line, filler neck hose, and seals. The testing was done per ASTM E96-66 “Thwing Albert” cup method which is a convenient process for screening various polymer materials.The data presented is in permeation rate units of grams-per-meter squared-per-day. The data suggest that fluoroplastics followed by high fluorine fluoroelastomers have the lowest average and peak permeation rates in fuel and fuel/alcohol blends.