The present work aims to investigate stability and decomposition of hydrate structure II of methane, propane, and isobutane systems at various temperatures, pressures, and compositions in the absence and/or presence of inhibitor molecules. To assess the stability of gas hydrates, a comprehensive knowledge of the structural, thermodynamic, and dynamic properties of the hydrates is needed. The structure II of gas hydrates is embedded in a molecular dynamic (MD) approach and the simulations are carried out under constant temperature constant volume (NVT) and constant temperature-constant pressure (NPT) conditions by employing the consistent valence force field (CVFF). In this work, first, the mean square displacement (MSD) and diffusion coefficient are evaluated to demonstrate the movement of host molecules. The radial displacement function is then utilized to display the characteristic configurations of structure II under different process and thermodynamic conditions. In addition, other vital properties including lattice parameter and potential energy are determined. The effect of inhibitors on stability and/or decomposition of hydrate structure II is investigated. The achieved results are in good agreement with previous theoretical and experimental outputs, confirming reliability and appropriateness of the simulation method. The inhibition capability of different inhibitors based on the simulation results has the following order: methanol > ethanol > glycerol. The findings of this study can help for better understanding of hydrate dissociation in molecular scale as well as for proper selection and design of effective inhibitors for hydrates with different structures and characteristics. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.