The paper concerns evaluation of initial stiffness in natural overconsolidated cohesive soils of various plasticity ranging from 10 to 80 %. Initial stiffness is here represented by shear modulus G_max determined on the basis of shear wave velocity measured at the end of consolidation stage during triaxial test. On the basis of representative number of tests it was shown that change in initial stiffness caused by mean effective stress increase is a soil kind dependent and can be described as a function of plasticity index. Some consideration concerning value of shear modulus for unconfined are also included. Thus, knowing both the above components it is possible to evaluate initial stiffness of overconsolidated cohesive soils solely on the basis of index properties.