The results of oedometer tests on intact samples of natural silty clays of Tehran are presented and compared with the corresponding results for reconstituted silty clays. Test program consisted of incremental load and constant rate of strain. By this means it has been possible to Identify the influence of the micro structure on the compressibility of natural silty clay. During the test program, variation of yield stress with depth, the effect of strain rate on the observed yield stress, and the creep behavior were investigated. The maximum creep occurred in the incremental load tests at yield stress but maximum swelling Index of destructured soil occurred before yield stress. These findings indicate clear relationship between creep and swelling with the structural break down at yield stress.