We present two sets of explicit relations for the equilibrium fugacities of single-guest gas hydrates. These relations can be applied whether the hydrate is dissociated under bulk conditions, or in porous media. The first set of presented relations explicitly shows the dependence of the equilibrium fugacity and the enthalpy of dissociation on classical statistical thermodynamic parameters. The second set of relations for the fugacity and enthalpy represent a very simple empirical form which can be used to calculate these quantities, without having to resort to the use of the full statistical thermodynamic model. it is hoped that these relations will prove useful in engineering or computational endeavors where the speed and/or ease of their use may be advantageous. (C) 2004 Elsevier Ltd. All rights reserved.