The solubility of nesquehonite (MgCO3 center dot 3H(2)O) and calcite (CaCO3) in carbonated water with CO2 pressure of between 1 and 5 MPa was measured from 293.15 to 343.15 K by the inductively coupled plasma optical emission spectrometry (ICP-OES) analysis method. The results showed that the solubility increased with CO2 pressure but decreased with temperature in all of the studied situations, and for the ones where the two solid phases coexisted, nesquehonite's solubility changed little from that of the single-existing cases while calcite's declined by 1 order of magnitude. The solubility was correlated with both temperature and CO2 pressure by empirical equations in a concise form.