Alcohol consumption is a well-established risk factor for hormone-dependent breast cancer. In vitro studies performed to understand the mechanisms by which ethanol acts on breast cancer cells have shown that this compound stimulates both proliferation and migration. In the present study, we show by gelatin zymography that, when exposed to ethanol, MCF-7 human breast cancer cells display a higher amount of active metalloproteinases (MMP) 2 and 9 in their culture medium. This increase is somewhat higher than those observed in the case of 17β-estradiol (E2) exposure. As expected, anti-estrogen ICI 182,780 inhibits the E2-induced overexpression of a well-known estrogen responsive gene, the progesterone receptor, in MCF-7 cells. ICI 182,780 also inhibits the E2-induced increase in MMP-2 and -9 secretion. Nevertheless, in the case of ethanol exposure, this ER ant-agonist was only efficient on MMP-9 secretion. In addition, although MMP-9 transcription was not sensitive to E2 or ethanol, MMP-2 transcription was stimulated in MCF-7 cells exposed to ethanol. Collectively, these results give new insights into the effects of alcohol on breast cancer cell migration, which are not due solely to an estrogen-like activity of alcohol.