the European Union, if necessary, an up to date classification for reprotoxicity according to Directive 67/548/CEE concerning classification, packaging and labelling of dangerous substances. Methods: Creation of a multidisciplinary working group within the French agency for environment and work (AFSSET); evaluation of available reprotoxicity studies: epidemiological studies in humans, following exposure of consumers and workers; controlled laboratory studies in animal species, generally tested for reprotoxicity and in other species when standardized. Results: 3 categories of substances were defined: mercury element, organic compounds (methylmercury and its chloride), inorganic compounds (mercury chloride). Mercury element: following occupational exposure in humans or studies in animals, appearance of disturbances of the ovarian cycle; for development, no effect in the general population in human (1 study) whereas effects in animals : reduction of the size of the litter, early deaths of pups, hyperactivity, abnormalities of behaviour, decrease in learning ability, histological abnormalities in monkey’s brain. Organic compounds: one study showing subfertility in man, 4 in animals of various species (decrease of mating for male, reduction of motility of spermatozoids, increase of ovarian cycle in females, disturbances in ability in reproduction); Following in utero exposures in human (acute poisoning of mothers during pregnancy or chronic exposures with low doses in diet), severe neurological effects occurred (mental retardation, blindness, deafness, retardation or absence of language, psychomotor retardation); in animals, an increase of death of embryos, teratogenic effects and neurobehavioral disturbances appeared without signs of toxicity in mothers. Inorganic compounds: for fertility, there is no data in human; in animals: decrease of the number of pregnant females, disturbances of the ovarian cycle, damages of testis; for development, no data available in humans; in animals, decrease of the size of the litter, and teratogenicity at massive doses of exposure. Discussion and conclusion: According to effects observed in humans or animals, proposals of classification for reprotoxicity are: mercury element: no classification for fertility and category 2 for development; organic compounds: category 3 for fertility and category 1 for development; inorganic compounds: category 3 for fertility and no classification for development. As newborn can be exposed during bread feeding because milk is a route for elimination of mercury, risk phrase R64 is asked for labelling of mercury and its compounds.