This review summarizes studies on the role of olive oil intake in the prevention and attenuation of mitochondrial oxidative stress derived from several situations such as ageing, physical exercise, treatment with adriamycin or intake of thermally oxidised oils. After more than fifteen years of studies on these issues, results have demonstrated that under different models of oxidative stress the regular intake of virgin olive oil as dietary fat is able to attenuate or increase free radical production at the mitochondrial level to a lower extent than when n-6 polyunsaturated oils are used. In the same way, virgin olive oil leads to better function of the mitochondrial electron transport chain.