This chapter investigates the potential effect of social relationships – composition of social networks and frequency of contacts among family and friendship networks – on whether elders retain or recover their robustness in very old age. Multilevel analyses were used to identify the short-term (12 or 18 months) effects of social relationships on robustness, after controlling for socio-demographic and health-related variables. Our analyses indicated that the existence of siblings had a significant impact on the maintenance or recovery of robustness, which was not the case with the other variables concerning the network composition. Paying visits to the family also had a beneficial effect on this health ourcome. Our results highlighted the importance of family relationships in the lives of the oldest old.