Recent ICSBEP meetings have shown the concern of the working group for uncertainties in reevaluated experiments. When using a reevaluation reported in the ICSBEP Handbook, the reader can encounter problems of different types: - he mixing of uncertainties on physical parameters either coming from a large number of measurements or given as tolerances, - the lack of information about the level of confidence and degrees of freedom corresponding to reported uncertainties, - inconsistencies in the reported level of confidence (corresponding to 1, 2 or 3 s) between the different uncertainties taken into account, - when the uncertainty on a physical parameter is converted in reactivity equivalent uncertainty, the total experimental uncertainty is given without mentioning the level of confidence.