This paper presents a polynomial time approximation algorithm for Multi-Robot Routing. The Multi-Robot Routing problem seeks to plan paths for a team of robots to visit a large number of interchangeable goal locations as quickly as possible. As a result of providing a constant factor bound on the suboptimality of the total distance any robot travels, the total completion time, or makespan, for robots to visit every goal vertex using this plan is no more than 5 times the optimal completion time. This result is significant because it provides a rigorous guarantee on time optimality, important in applications in which teams of robots carry out timecritical missions. These applications include autonomous exploration, surveillance, first response, and search and rescue.