In this paper, we investigate the leader-follower formation control of underactuated Autonomous Underwater Vehicles (AUVs). By using position measurements from the leader, we design a virtual vehicle such that the trajectory of the virtual vehicle converges to the reference trajectory of the follower. A position tracking control is designed for the follower to track the virtual vehicle using Lyapunov and backstepping synthesis. Simulation results demonstrated the effectiveness of the proposed scheme.