This paper addresses the multi-robot 2-cyclic scheduling problem in a no-wait robotic cell where exactly two parts enter and leave the cell during each cycle and multiple robots on a single track are responsible for transporting parts between machines. We develop a polynomial algorithm to find the minimum number of robots for all feasible cycle times. Consequently, the optimal cycle time for any given number of robots can be obtained with the algorithm. The proposed algorithm can be implemented in O(N 7 ) time, where N is the number of machines in the considered robotic cell.