Shear strength is one of the most important mechanical properties of soil during construction. It is conditioned by the value of a maximum shear stress that a soil can withstand before failure. Exceeding the shear strength causes one particle to slide next to another, which results in soil failure. The shear strength of soil for effective stresses is a combination of drained strength parameters: internal friction angle (φ) and cohesion (c) defined by Mohr-Coulomb failure law. It is determined “in situ” and by laboratory experiments. Direct shear is considered to be the oldest and the simplest laboratory experiment which is used for determining the shear strength of soil. In the first phase of an experiment, a sample is consolidated under a certain vertical stress, and in the second phase it is sheared at a given velocity depending on drainage conditions, permeability and thickness of the sample. Incoherent soils are sheared at high speed, while for coherent soils lower velocity is needed. Shear velocity and drainage conditions affect the magnitude of soil strength parameters. The paper is based on the comparison and demonstration of the influence of different shear velocities on the shear strength of low plastic clay in a direct shear device.