The obesity epidemic has resulted in more women entering pregnancy overweight or obese. Offspring of obese women have increased risk of obesity and impaired glucose tolerance in childhood and adult life. It has therefore been proposed that there is an ‘intergenerational cycle’ of obesity and insulin resistance. Studies have shown that changes in the abundance of insulin signalling molecules in skeletal muscle and adipose tissue precede the development of insulin resistance and type 2 diabetes (1,2). It is not clear, however, whether exposure to maternal obesity results in insulin resistance in her offspring as a consequence of the impact of increased adiposity on insulin sensitive tissues (3,4) or as a consequence of the programming of specific changes in the abundance of insulin signalling molecules in these tissues (2,5). It has previously been shown in sheep that exposure to maternal obesity around the time of conception alone led to increased adiposity in female lambs at 4 months of age and that dietary restriction in the obese ewe during the periconceptional (PC) period abolished this effect (6). While dieting before pregnancy may have metabolic benefits for the offspring, there are also potential metabolic and endocrine costs for the offspring (7). The pathways and critical periods during which the metabolic consequences of maternal obesity or dietary restriction are transduced from mother to the offspring are, however, not known. Moreover, there is a paucity of knowledge on the possible epigenetic mechanisms that are recruited in the oocyte/early embryo, which could contribute to such changes. We used an embryo transfer model in sheep to investigate the effects of maternal obesity and of dietary restriction during the PC period on insulin signalling in liver and skeletal muscle of the offspring. Furthermore, we also investigated the role of miRNAs in regulating hepatic insulin signalling in these offspring. Donor ewes were allocated to 1 of 4 groups & were fed the following diets in the PC period: 100% metabolisable energy requirements (MER) for ≥ 20wks (CC); 100% MER for ≥ 16wks & then 70% MER for 4wks (CR); ~180% MER for ≥ 20wks (HH); ~180% MER for ≥ 16wks & then 70% MER for 4wks (HR). This continued for 1wk post-conception before single embryos were transferred into recipient ewes of normal weight. At 16wks after birth, liver and skeletal muscle samples were collected to determine insulin signalling gene expression (by qRT-PCR) and protein abundance (by Western Blotting) and expression of key miRNAs (by qRT-PCR) in the offspring. The effects of PC nutrition and sex on protein abundance and miRNA expression were determined using a two-way ANOVA. A Duncan’s post hoc test was used to determine significant differences between groups. We found decreased insulin receptor (IR) (P<0.05), Akt2 (female lambs) (P<0.05), phospho-Akt (P<0.01) and phospho-FoxO1 (P<0.01) abundance and in contrast, an increased Caveolin-1 (P<0.05) abundance in the liver of HH lambs. There was a parallel increase in miR-29b (P<0.05), miR-103 (P<0.01) and miR-107 (P<0.05) expression in these lambs. Maternal dietary restriction abolished some of the effects of maternal obesity. The abundance of Akt2, however, remained low (female lambs) and Caveolin-1 and miR-103 remained increased in HR lambs. Furthermore, there was decreased hepatic PDK1 gene expression (P<0.01) and phospho-PDK1and aPKCζ protein abundance (P<0.05) in CR and HR lambs. In contrast to the liver, maternal obesity resulted only in decreased GLUT4 abundance in muscle of female lambs. There was, however, increased IR abundance and decreased aPKCζ, phospho-AS160 and GLUT4 abundance in both CR and HR lambs. We have found that exposure of the oocyte/early embryo to maternal obesity leads to differential changes in gene expression and protein abundance of key insulin signalling molecules in liver and muscle in postnatal life. Our results also suggest that miRNAs may be potential epigenetic regulators that are sensitive to programming by the maternal metabolic/nutritional environment and may play a key role in transducing the metabolic consequences of maternal obesity from the mother to her offspring. Importantly, we also found that in most instances, dietary restriction was unable to ablate the effects of maternal obesity in both liver and skeletal muscle of lambs. Instead, exposure to dietary restriction itself irrespective of whether the ewes were previously on a normal or high plane of nutrition led to changes in a different suite of molecules within both liver and skeletal muscle of the offspring. These results suggest that maternal metabolic response to weight loss around conception, irrespective of her pre-pregnancy body weight has long lasting metabolic consequences for the offspring, which may contribute to the emergence of insulin resistance in later life.