The effect of myoglobin (Mb), hemoglobin (Hb), hemin (Hm) and the preformed cooked cured-meat pigment (CCMP), as well as Fe(II), Fe(III), Cu(I) and Cu(II) on the oxidative stability of cooked comminuted pork was studied over a 21 day storage at 4°C. All these compounds, except CCMP, had pro-oxidant activity. The pro-oxidant effect of metal ions was more pronounced at their lower oxidation state, as measured by the 2-thiobarbituric acid (TBA) test. Addition of chelators, disodium salt of ethylenediaminetetraacetic acid (Na2EDTA), and to a lesser extent sodium tripolyphosphate (STPP), inhibited the pro-oxidant activity of the above compounds, Addition of metal ions to the meats after cooking similarly enhanced the autoxidation of lipids in the above systems, thus reflecting the importance of processing conditions and equipment wear-out on the oxidative state of precooked meat products.