Uniaxial compressive strength and undrained shear strength are among the most important soil parameters in geotechnical engineering. The unconsolidated undrained triaxial test and the falling cone test determine them. The uniaxial compressive strength of soil is the maximum compressive stress that the soil can withstand before failure in drained conditions. In contrast, the undrained shear strength of the soil represents the maximum shear stress that the soil can withstand before failure in undrained conditions. In this paper, using modular clay as an example, the results of laboratory tests that determine these parameters according to Croatian standards are presented and compared.