The decomposition kinetics of nanocrystalline calcite is investigated using the master plot method and Coats and Redfern's equation. It is shown that the nanocrystalline calcite as well as the reference calcite dissociates according to the contracting volume mechanism R-3. Comprehensive techniques have been used to determine the kinetic parameters. A considerable diminution of the activation energy E-a up to 70-80 kJ mol(-1) is observed in the case of nanocrystalline calcite. In addition, the kinetic compensation law has also been used to correlate the pre-exponential factor A with the activation energy E-a.