Four laboratories measured the short fiber content and other fiber properties of 45 commercial and experimental cotton fiber samples on high volume instrument (HVI), Suter-Webb Fiber Sorter, Advanced Fiber Information System (AFIS), and Peyer Almeter testing machines. The variation of short fiber content and average value differences among different testing machines were high. The correlation coeeficients of the short fiber content measured by the different methods and different measured by the different methods and different laboratories were lower than other fiber length parameters. The accuracy and precision of the Suter-Webb Array Method, which is the reference emthod for fiber length measurement, were limited for short fiber content. Although AFIS and Suter-Webb Array methods had widely varying values for short fiber content, other test results demonstrated a high correlation coefficient. Additional tests entailing HVI and AFIS testing of a long-strong and a short-weak cotton showed that the variation of short fiber content was much higher for the short fiber sample. Abstract.