The aim of this work was to determine how ageing changes were related to each other by studying the establishment of a senescent state in cell culture, rabbit articular chondrocytes. A striking increase of the amount of peroxides appeared at 2/3 of the time of cell growth, which is responsible for an oxidative stress, as shown by the appearance of oxidized proteins, the overexpression of HSP27 gene and the accumulation of HSP27 protein. While no change of the mitochondrial membrane potential was observed all along the cell culture, p21, a protein overproduced in senescent cells, appeared with the peak of peroxides and accumulated.