A newly developed cotton fiber strength testing ma chine, known as the Pressley Cotton Fiber Strength Tester, has been found to provide results which are highly correlated with those obtained by the well-known Chandler round-bundle method of determining tensile strength of cotton fibers. The tests on the new machine can be made about 6 to 8 times as rapidly as with the Chandler method, and therefore its adoption is rapidly taking place in various cotton fiber testing laboratories. The following article briefly summarizes the report of a series of tests conducted at the Stoneville Cotton Testing Laboratory of the U. S. Department of Agricul ture. A comparison was made of the results obtained upon a large number of varieties of cotton by different operators using eight different Pressley machines. The complete report can be obtained from the Department. 1