Title : On the complexity of single machine scheduling problems under scenario-based uncertainty Mohamed Ali Aloulou - Federico della Croce LAMSADE - Paris Dauphine In this paper, we are interested in scheduling environments where some job characteristics are uncertain. This uncertainty is modeled through a finite set of well-defined scenarios. In such a context, we search for a solution that is acceptable for any considered scenario. For this purpose, several criteria can be applied to select among the solutions. We use here the so-called maximal cost criterion. We present algorithmic and computational complexity results for several single machine scheduling problems.