Stress-corrosion tests were made on 18 alloys. The corroding agents were the products of combustion of leaded aircraft gasoline. Tests were made under both constant temperature and cyclic temperature conditions. Under the conditions of these tests, the combustion products are somewhat corrosive if the temperature is cycled but not at constant temperature. The acceleration of strain due to temperature cycling alone has a greater detrimental effect on strength. From the results of these tests, certain speculations are possible concerning the process by which products of combustion of leaded gasoline cause corrosion.