Epidemiological studies provide evidence that mechanisms defining weight and body composition during development impact upon obesity in latter life. Impairments of energy supply during the pre and post-natal periods could indeed impact on energy partitioning, modifying intrauterine and postnatal growth performances. As part of the EARNEST European research programme, this study aimed to modify pre and post natal growth in the sheep model for further analysis of the developmental origins of metabolic diseases. 30 twin-bearing ewes entered the study. During the last third of pregnancy (110 day to term), sheep were divided into two groups: 1) Undernourished (UN, n= 20) receiving 60 % of energy requirements and 2) Controls (C, n= 10) receiving 100 % of requirements. Sheep gave birth naturally at term (147 days). UN offspring were separated in two groups according to maternal diet. 20 were reared as twins (UN-T) and 10 as singletons (UN-S). C offspring (n=10) were reared as singletons (C-S). Body weights from birth to weaning (3 months old) were weekly measured during the first month and on a 2 weeks basis thereafter. Body weight differences and fractional growth rate (FGR) were analysed using SPSS software. All experimental protocols had the required Home Office approval as designated by the Animals Act (1986). Compared to controls, UN offspring were lighter at birth (p<0.01) and remained lighter throughout the entire lactation (p<0.05). Although UN-S were smaller than C-S, they grew relatively faster. Indeed, FGR showed that weight at weaning was 6.5 +/- 0.32 and 5.6 +/- 0.24 times the birth weight respectively for UN-S and C-S (p<0.01). As compared to UN-S, UN-T had a lower growth rate (p<0.05). UN-T females weight during the entire lactation did not differ from UN-S females whereas male twins were lighter than UN-S males at mid lactation (p<0.05) and weaning (p<0.01). Finally, despite no differences at birth, at the end of weaning, both UN-S and C-S females were lighter than males (p<0.05). This is not true for UN-T. A 60 % caloric reduction during late pregnancy impacted intra-uterine growth and produced small birth weight offspring. Interestingly, compared to C-S, UN-S showed higher growth performances in the early postnatal period suggesting a long lasting effect of intra uterine growth retardation. As expected, female singletons were lighter than males. Nevertheless, twin males were not heavier than females suggesting a growth impairment dependent upon gender. Taken together, these data showed perturbations of pre and post-natal growth due to foetal restriction and/or postnatal environment which are predicted to have further long-term effects on adipose tissue development and metabolic control. These extended studies are currently underway Acknowledgements: This work was supported by the Early Nutrition Programming European project (EARNEST)