Preconceptional or inter-pregnancy weight loss is often recommenclecl to obese future mothers as a preventive action to protect offspring clevelopment from deleterious effects of endocrine impairments du-ring pregnancy and lactation. However, the benefits of such a maternal weight control on offspring long-term health remain poorly investigated. Olfactory sensitivity and associated behaviours are influenced by the metabolic status (1-2). Ils alteration has been described in varions diet-induced inoclels of metabolic imbalances, such as diet-induced obesity (3) and calorie restriction (4) or in bariatric surgery studies (5). As maternal environment could impact progeny health at long-term according to the known DOHaD concept, we investigated the effect of pre-gestational maternal weight control on off­ spring olfactory sensitivity in a mouse model recently developed (6): Mice were either fed with a control diet (CD) , a high-fat diet (HFD) or a HFD switched to a CD one 2 months before conception to induce a weight loss (WL) . After birth, pups were divided in two groups at weaning and were fed with CD or HFD for 5 months. Metabolic measures revealed clear-cut endocrine differences in offspring reflecting their diet status. Animals were tested for their olfactory-based behaviour in a buriecl cookie test and a 2-hole board olfactory preference test. The post-weaning diet predominantly influenced pu p's olfactory sensitivity and preferences as compared to the maternal one. Interestingly, maternal weight loss didn't prevent the development of olfactory impairments observed as early as after 3 weeks uncler a HFD, i.e. much before the appearance of endocrine alterations in the offspring. Surprisingly, we observed that peripheral olfactory mucosa neuronal response was clearly diminished in the electro-olfactograms recorded after 5 months of diet in offspring barn from WL mothers regardless the postweaning diet, compared to those born from CD and HFD mothers. We conclude that post-weaning cliet recommendations are essential to optimize the preventive effect of a pre-gestational or gestational weight loss on the development of olfactory impairments that could participate to food intake deregulation. If the maternal preconceptional weight loss only partially counteracts post-weaning diet consequences, its intergenerational eff'ect on peripheral olfactory sensi-tivity should be further investigated at molecular level.