In this communication, we report hydrate dissociation conditions for the methane+cycloheptane/cyclooctane+water and carbon dioxide+cycloheptane/cyclooctane+water systems. The experimental data were generated using an isochoric pressure-search method. The dissociation data for clathrate hydrates of cycloheptane or cyclooctane+methane are successfully compared with the literature data demonstrating the reliability of the literature data and the experimental method used in our work. The experimental data for all measured systems are finally compared with the corresponding literature data in the absence of cycloheptane or cyclooctane to study the hydrate promotion effects of the latter two chemicals. (C) 2010 Elsevier Ltd. All rights reserved.