This paper analyzes the characteristics and instability of the hillslopes on the hornfelsic residual soils in south and southwest Hamedan city based on field investigations and various labratory tests. For this purpose, the limit equilibrium analyses are performed to determine the factor of safety and sensitive analysis against slope failure of residual soil slopes. The sensitivity and stability analyses with respect to varying slope angles, shearing strength parameters, and thicknesses of saturated residual soil were performed. The results indicated that the southwest parts of Hamedan have high potentiality of translational slide even in 30 to 60 % saturation of soil layer depending on the slope angles and vertical depth of the soil. In this area, the threshold slope angles to failure vary between 23.5 to 41 degree. The remediation measurements in order to decrease the possible damages are recommended.