Three different measures of fiber strength, stelometer-T(1), HVI-Motion Control and HVI-Spinlab, were compared and related to yarn strength. The data were taken from San Joaquin Valley Acala Cotton Board trials from 1983 to 1987. Simple correlations between fiber and yarn strength indicated that the Motion Control HVI line, on average accounted for less than 15% of the variation in yarn strength. The stelometer readings on average accounted for 47% of the variability, and the Spinlab HVI was midway between the two. Multiple correlations using fiber strength plus length, uniformity and micronaire data resulted in a greater relative improvement in the relationship in the case of the HVI data, particularly with the Motion Control line, but the ranking remained unchanged from that of the simple correlation.