The contribution is focused on investigation of strains in a rock specimen during uniaxial compression test. Three components of strain occur in cylindrical shape specimen: axial, radial and volumetric. Determination of the strains is possible by using of local sensors. Strain gauges fixed on specimen surface were used in this study. Axial and radial components of strain were measured directly, and volumetric strain was calculated. Two types of rock were tested, syenite and sandstone, to illustrate variability of strain behaviour of rocks. Strain measurement is necessary for determination of Young’s modulus and Poisson’s ratio. Moreover, early states of failure can be identified by volumetric strain which is considerably sensitive to failure states.