In this work, experimental dissociation data for semi-clathrate hydrates of tetra-n-butylammonium bromide + hydrogen sulfide and tetra-n-butylammonium bromide + methane are reported in the temperature range of (290.9 to 295.7) K and (283.6 to 290.1) K, respectively at 0.05 mass fraction of tetra-n-butylammonium bromide in aqueous solution. The experimental data were generated using an isochoric pressure-search method. The hydrate dissociation data for the tetra-n-butylammonium bromide + methane system are compared with the corresponding experimental data reported in the literature, and the acceptable agreement demonstrates the reliability of the experimental method used in this work. The experimental data for both measured systems are finally compared with the corresponding experimental data in the absence of tetra-n-butylammonium bromide reported in the literature to study its hydrate promotion effect.