Genetic parameters were estimated for numbers of piglets born in total (TNB), born alive (NBA), stillborn (NSB) and weaned (NW) per litter, birth to weaning survival rate (SR), farrowing duration (FD), litter weight and within-litter standard deviation of individual piglet weight (SDPW) at birth. Data were collected on 29,153 and 16,354 litters in Large White (LW) and French Landrace (LR), respectively, between 2002 and 2005. The analyses were carried out using restricted maximum likelihood methodology. All traits were analysed using a mixed linear animal model including herd, year x month and parity as fixed effects, the additive genetic value and the permanent environment of each sow, as well as sire of litter, as random effects. Low heritability estimates were obtained for litter size (0.10 to 0.13) and mortality traits (0.06 to 0.11). NSB had unfavourable genetic correlations with TNB (0.49 and 0.56 in LW and LR, respectively), but low genetic correlations with NBA (0.05 and 0.18). Both TNB and NBA showed a genetic antagonism with SR (–0.24±0.09 to –0.32±0.07). The number of stillborn was positively correlated with FD at the genetic level (0.64±0.08 and 0.41±0.09 in LW and LR, respectively). Litter weight was positively correlated with litter size and had low (LR) to moderate (LW) genetic correlations with SR. SDPW was genetically associated with lower SR (-0.21±0.18 to –0.28±0.33 in LW and LR, respectively).