An assembly sequence planning scheme, giving the time optimal solution for a two-robot cell, is presented. The scheme is based on dynamic programming, and the time optimum assembly sequence is generated in two stages. In stage one, an initial candidate sequence is derived. The stage-one algorithm is computationally efficient, the complexity being O(log n/k), where n is the number of elements in k groups. It also gives near-optimal results. Expression for the lower bounds for the total assembly time are derived in order to assess the departure from optimality of the stage-one sequence. In stage two, the initial candidate sequence is optimized using an iterative technique to yield the time optimal sequence. The scheme is extended to account for precedence constraints. It can also be extended for assembly cells with more than two robots. The scheme is tested using computer simulations, and some test results are presented. For the problems solved (typically involving 20 elements), the computational times were less than 5 sec in an Apollo 300 workstation.