The coefficient of linear extensibility (COLE) is a quantitative expression of the capacity of a soil to swell when moist and to shrink and crack when dry. COLE values are used to characterize soils in their natural condition and to group them according to their swelling tendencies. They are useful in predicting potential swelling problems with agricultural and engineering connotations in given soil areas. The relationship of COLE to other soil parameters was studied using data from 68 horizon samples of Vertisols, Mollisols, Ultisols, and Oxisols from Puerto Rico. Soil parameters studied were percent clay, silt and organic carbon. While for Mollisols and Vertisols COLE values were highly correlated with percent clay (R2 = 0.743 and 0.637, respectively, p< 0.01), in Ultisols the most significant variable was found to be percent organic carbon (R = 0.511), with negligible contributions of silt and/or clay. For Oxisols, an interaction between percent organic carbon and clay was found to be highly significant (p< 0.01), accounting for 85% of the variability in COLE values. Other factors, such as clay minerals may have an effect on the COLE values observed.