Vegetation acts as a reinforcement for slopes due to the penetration of roots into the ground. Roots penetration is a time dependent phenomenon that is strongly connected to the hydrogeological condition of the slope and that interacts with soil properties. Roots reinforcement of soil is well documented and numerous formulae exist in literature. The reinforcement action is provided by roots penetrating below a potential slip surface and stiffening the slope. Roots contribution to stability depends both on roots tensile strength and on roots pull-out resistance. Both aspects have already been investigated and some models and formulae already exist which enable a qualitative evaluation of such contribution. Anyway no sophisticated software exists for the prediction of the three-dimensional numerical analysis of slope stabilized with vegetation. Existing software provides simple limit equilibrium analyses and is limited to plane problems. This research project joins together scientific expertise and numerical know-how to implement latestadvances in slope reinforcement with vegetation into commercial software. The resulting software will enable three-dimensional reinforced slope modeling. It will provide realistic soil-root interaction and root constitutive models. It will take into account roots growth with time and it will consider variations of the watertable and unsaturated conditions.