Tumour-Necrosis Factor Alpha (TNF-α) is a pleiotropic cytokine that is chronically elevated in ageing/aged related disease states (Sarcopenia, Cachexia); where higher TNF-α levels are strongly correlated with morbidity and mortality in later life. We have extensively shown that TNF-α impairs regenerative capacity in mouse and human muscle cells (Meadows 2000; Foulstone 2001, 2004; Stewart 2004; Al-Shanti 2008; Saini, 2008; Sharples 2010). Recently, we have established a SIRT1 (histone deacetylase) mediated mechanism regulating survival of myoblasts in the presence of TNF-α (Saini, 2012). We therefore wished to extend this work and investigate the epigenetic consequences of repeated doses of TNF-α on DNA methylation. C2C12 myoblasts were cultured in the absence or presence of TNF-α (40 ng.ml-1), followed by multiple population doublings (25 doublings; Sharples et al., 2011, 2012) in the absence of TNF-α, prior to the induction of differentiation in the absence or presence of a second dose of TNF-α (20 ng.ml-1). Interestingly, the cells that received a pre- and post-population doubling dose of TNF-α were more susceptible to the cytokine and exhibited a larger reduction in morphological and biochemical (CK) differentiation vs. cells that had not been exposed to TNF-α previously. Interestingly, CpG island methylation of 3 different regions of myoD were increased in cells that have undergone the ‘early life’ TNF-α dose with corresponding reductions in myoD gene transcription. Overall, myoblasts seem to have a memory of earlier life encounters of TNF-α when exposed to a further catabolic stimulus in later life, potentially through increased CpG methylation of myoD.