Ageing is characterised by a loss of muscle mass (sarcopenia). The mechanisms contributing to this loss are not known. One theory is that sarcopenia results from impaired regeneration after contraction-induced injury. Muscle repair is mediated by satellite cells and there is evidence that satellite cells from both young and old donor animals are equally able to proliferate in vitro and populate the regenerating, damaged muscles of young animals in vivo (Collins et al., 2007). This suggests that the satellite cells themselves are not affected by age, although their responses are impaired by the aged systemic milieu (Conboy et al., 2005). The aim of this study was to determine whether satellite cell derived myoblasts extracted from elderly and young humans differ in their ability to proliferate and differentiate in culture. Needle biopsies were taken under local anaesthesia (2% lignocaine) from the vastus lateralis muscles of 6 young (aged 23-26 yrs, 3 males 3 females) and 5 older (aged 80-81 yrs, 3 females, 2 males) subjects. Serum was obtained from one young male (aged 24 yrs). Visible fat and connective tissue was removed from the biopsy sample and the remaining muscle was digested with trypsin (5mg/ml). Cells were collected by pelleting and cultured in skeletal muscle cell growth medium (SMCGM) supplemented with 10% foetal calf serum in 96 well dishes. After 24 hours the SMCGM was replaced with basal skeletal muscle medium supplemented with 15% serum for proliferation or 2% serum for differentiation experiments. Cells were fixed after 46 hours (proliferation experiments) or 11 days (differentiation experiments) in 4% paraformaldehyde + 0.2% triton. Proliferation was determined as the number of desmin (muscle cell marker) positive muscle cells that also stained for Ki67 (a proliferation marker). Differentiation capacity was determined by counting the number of nuclei (counterstained with Hoechst) in myosin heavy chain positive cells relative to the total number of nuclei in the culture. Two wells were studied per condition and the mean value used for analysis, counting at least 500 cells per well. The data revealed no differences (unpaired t-test) in proliferation of myoblasts obtained from the elderly (33.0+/-6.9%, mean +/-SEM) compared to the young (32.1+/-6.9%) subjects. Likewise, the differentiation of myoblasts from the elderly subjects (54.8+/-22.4%) was no different compared to that of young subjects (59.6+/-10.4%). The data suggest that age does not affect the ability of human myoblasts to proliferate or differentiate in culture.