Cow's, ewe's, and goat's milk samples were treated with carbon dioxide gas until a pH of 6.1 was reached and stored at 4 degrees C to determine the resulting modifications in the mineral balance. The amounts of calcium and phosphorus dissolved during the acidification were similar in the three species. The acidification with CO2 produced the dissolution of phosphorus and magnesium in concentrations similar to those attained by acidification with lactic acid or hydrochloric acid. Still, the contents of soluble calcium and ionic calcium were higher with the CO2 treatment. The increase of ionic calcium due to the addition of CO2 could explain why milk subjected to such treatment is better suited for coagulation. Removal of added CO2 by shaking the milk for several hours at atmospheric pressure resulted in a higher concentration of ionic-calcium than was found in control milks to which no CO2 had been added. Thus the addition of CO2 improved milk's technological suitability for cheesemaking.