The identification of a local excess of cancer cases, possibly associated with ionizing radiation, always receives substantial media coverage and communication about clusters is difficult. We reviewed studies that examined the risk of leukaemia among young people near nuclear installations. An excess of leukaemia exists near some nuclear installations, at least for the reprocessing plants at Sellafield and Dounreay and the nuclear power plant Krmmel. Nonetheless, the results of multi-site studies invalidate the hypothesis of an increased risk of leukaemia related to nuclear discharge. Up until now, analytic studies have not found an explanation for the leukaemia clusters observed near certain nuclear installations. The hypothesis of an infectious aetiology associated with population mixing has been proposed, but needs to be investigated further. The review illustrates two recent examples in France (La Hague reprocessing plant) and in Germany (Krmmel power plant), where controversies developed after reports of increased leukaemia risks. These examples show the importance of recalling the current epidemiological knowledge and of using systematic recording of cases to replace the alleged excesses in a more general framework. Some elements should also be suggested from the recent French and German experiences to reinforce credibility in the results.