After in vitro maturation, the unfertilized pig oocytes underwent the process called ageing. This process involves typical events such as fragmentation, spontaneous parthenogenetic activation or lysis. Inhibition of histone deacetylase, using its specific inhibitor trichostatin A (TSA), significantly delayed the maturation of pig oocytes cultured in vitro. The ageing of oocytes matured under the effect of TSA is the same as the ageing in oocytes matured without TSA. The inhibition of histone deacetylaseduring oocyte ageing significantly reduced the percentage of fragmented oocytes. The parthenogenetic development in oocytes aged under TSA treatment is similar to the development of fresh oocytes (29% of blastocyst) artificially activated immediately after in vitro maturation.