The purpose of the investigation reported in this paper was to study the influence of strain rate on stress-strain and strength relationships of Mexico City lacustrine soils from the Central Park site (Alameda). An isotropic consolidation test to define the yielding stress, σ'_y(=95kPa), was done by triaxial-cell method. The paper describes results from 16 consolidated-undrained triaxial compression tests on Mexico City lacustrine soils. Specimens were consolidated to four confinement pressures (σ'_c=40, 80, 160, and 300 kPa), and for each, σ'_c, undrained shear was performed using four axial strain rates (1%, 5%, 100%, and 800%/h). The results show that the peak shear resistance increased about 336% in passing from the slow to the fast strain rate for the structured domain. For destructured domain, the increase was about 229%.