The focus of this contribution is on numerical simulation of processes with moving deformable interfaces involving a soluble surfactant. Resolution of the interface is based on the Volume-of-Fluid (VOF)-method. The current numerical approach is applicable to diffusion controlled processes, where the relation between the area-specific surfactant concentration on the interface and the volume-specific concentration in the sub-layer adjacent to the interface is given by an adsorption isotherm. The change in time of the amount of surfactant within a fixed control volume containing interface is determined by diffusive and convective fluxes both in the bulk phase and on the interface and by advection of the interface itself. Simulations are done with the commercial CFD-solver Fluent 6.1. A source term for the surfactant transport equation in the continuous phase which accounts for interfacial stretching is implemented. For proper discretization of the diffusive interfacial fluxes and the additional source term, a reconstruction of the interface by means of a continuous iso-surface with respect to the VOF-variable is used.