Here is the revised version of my paper "Robust Timing of Markdowns", written with Michael Dziecichowicz and Daniela Caro. It considers a product sold over a selling horizon at various decreasing prices by a retailer and applies robust optimization to the uncertain demand arrival rates. A key feature of this paper is that, because the time during which the product is put on sale at a given price is a decision variable, the argument of the (concave) budget of uncertainty is itself a decision variable, introducing non-convexities in the formulation. We show how to solve the problem in a tractable manner. We also show that, under a mild condition, there is one optimal sale time (two distinct selling prices) in the selling season when the budget of uncertainty is concave. We also implement a dynamic policy and demonstrate its potential on numerical experiments, and extend the setup to the case of multiple products.