A simple and facile solution-phase method has been developed for the fabrication and growth thermodynamic studies of CdS nanocrystals (NCs) using isothermal titration calorimetry (ITC). Monodispersed and uniform CdS NCs with diameter less than 10 nm have been successfully obtained by controlling the preparation conditions. Meanwhile, the growth thermodynamic properties were observed in situ using ITC. Studying on the thermodynamics of nanomaterials makes significant advances in our understanding of its growth mechanism, as well as the correlation between thermodynamic data and structure. Optimization process of synthesizing target nanomaterials can also be realized. (C) 2010 Elsevier B.V. All rights reserved.