Both birth weight of the individual piglet and the intra-litter variations of birth weight are of considerable economic interest for pork production. Not only the survival rate within the first week after birth, but also postnatal growth (preweaning, nursery and grow-finish period) is impaired in low compared with high birth weight pigs (Quiniou et al., 2002). Over the last decade, sows have been selected that have the ability to give birth to a higher number of piglets. This has led to an increased within-litter variation in piglet birth, as well as an overall decrease in birth weight. This paper will focus on: 1) the consequences of impaired prenatal growth on myogenesis (prenatal skeletal muscle development) and 2) the impact of differences in birth weight on postnatal development, carcass characteristics, and meat quality traits. In the pig, myogenesis has two stages and involves determination, migration, proliferation, differentiation, and fusion of myoblasts to form myotubes (primary myofibers). In the second stage over 20 secondary myofibers appear around each primary myotube using them as a scaffold. The total number of myofibers formed is lower at birth in smaller compared to larger fetuses. The survival rate as well as the postnatal growth performance, carcass characteristics and meat quality can be compromised by low birth weight, because myofiber number and size are related with these traits. The results from a recent feeding trial suggest that in low birth weight pigs, ad libitum feed access favored adipose tissue accretion, resulting in fatter carcasses at market weight. Thus, it seems unlikely that postnatal feeding strategies are effective in overcoming the demonstrated effects of low birth weight. Maternal feeding during gestation has also not been shown to be very effective in improving fetal growth. Genetic selection for litter homogeneity seems to be the only suitable tool for improving fetal muscle growth and ultimately pork quality.