Results of residual shear strength of cohesive soils derived from landslide-prone areas in Szymbark near Gorlice (the Flysch Carpathians) are presented in the paper. Shear tests were done using direct shear strength apparatus on samples of dimensions 60 × 60 mm. Two shearing rates were applied: 0,05 and 0,1 mm per min. Each sample were repeated sheared six times and rate of horizontal deformations of samples were equal 20%. Test results revealed that the residual shear strength formed along the plane of weakness is of 52–78% of its maximum strength and to its produce at least 5 repeated series of shearing should be done. Effect of shearing rate on the obtained values of residual strength was inconclusive. It was also revealed that interpretation of test results using linear equations using Coulomb-Mohr failure criterion can give nonzero values of the residual cohesion. It was stated that for purpose of reduction of the impact of this parameter for the assessment of slope stability calculations it can be used non-linear envelope of shear strength described by Lade’s equation.