This paper presents a real-time simulation of a virtual surgical suture, which is a physically-based model adapted from the Cosserat theory of elastic rods. The focus is on achieving a physically plausible simulation of the suture that can be simulated in real time. With simulation parameters adjustment, the virtual surgical suture can be accustomed to exhibit bending and twisting similar to a real suture. It is simple to implement and easy to extend for collision detections and interactions with other virtual objects. Its simulation is similar to a simulation of a composition of two mass-spring chains – for positions and orientations. Test results show that the virtual surgical suture can be used to tie knots in real time.