It is well established that biological aging is associated with functional deficits at the cellular, tissue, organ and system levels, but the molecular mechanisms that control lifespan and age-related phenotypes are still not well understood. In order to investigate the molecular mechanisms underlying myoblast aging, we have used quantitative hybridization of a cDNA array of 2016 clones from a human skeletal muscle 3'-end cDNA library to monitor gene expression patterns of myoblasts of individuals with different ages (5 days old, 52 years old and 79 years old) and at different stages of proliferation (early, presenescent and senescent). We have shown that expression profiles in satellite cells vary with donor age, with an up-regulation of genes involved in muscle structure, muscle differentiation and in metabolism in the newborn, and a down-regulation of genes involved in protein renewal in adults. We have also observed that myoblasts isolated from subjects of different ages have typical expression profiles at the beginning of their proliferative lifespan. However, this phenomenon progressively disappears as the cells approach senescence. In addition, even though some of the modifications are similar to those observed in other cell types, we have observed that many changes in gene expression are characteristic of the myoblasts, confirming the hypothesis that the program of replicative senescence is specific for each cell type. Finally, we have identified four potential new markers of presenescence for human myoblasts, which could be useful in developing therapeutic strategies.