Kinematic and static analysis of geotechnical problems using the DEM has been widely accepted in the research arena for many years; however, its routine use in geotechnical practice for slope stability analysis still remains limited. This study focuses on the behavior of cohesive soil slopes undergoing failure initiation and succedent run-out. The numerical simulations of a supposititious slope composed of homogeneous cohesive soil were conducted using the DEM. The cohesive soil was simulated using contact-bonded graded aggregates of diameters ranging from 80 to 160 mm. This study investigated the microcrack-growth, particle displacements, particle movement and porosity changes within the slope fill. The simulation results showed that the failure mechanism is a rotational one at the failure initiation stage and gradually transfer to a slide/flow mode as progressive failure occurs. The porosity of deposit mass increased remarkably as result of dilation and block void. The run-out behavior of failure mass is not very sensitive with the viscous damping constant.