Large amount of data on single fiber tensile properties have been obtained from a Mantis® tester developed by Zellweger Uster. The distributions of single fiber tensile properties were examined and the independency between them was examined. The single fiber loadelongation curves have been superposed to simulate the tensile behaviors of classical bundles and bundles with fiber crimps. Large and small bundle tensile behaviors of cotton fibers have been examined through the simulation. Loss of bundle strength efficiencies has been examined as a function of the variances of the single fiber breaking elongations and the fiber crimps. The tensile properties of simulated bundles were compared against that from HVI tests.