In this Article, experimental data on compositions of equilibrium phases under gas hydrate formation conditions are reported for the carbon dioxide + nitrogen + water system in the (273.6 to 281.7) K temperature range for pressures up to 17.628 MPa. An experimental "in-house" setup based on the static analytic technique was employed for performing the measurements An isochoric pressure-search method in combination with gas phase compositional analysis was used to measure compositions of the gas phase in equilibrium with gas hydrate and liquid water. A material balance method was used to determine compositions of the hydrate and aqueous phases. A mathematical approach based on the Newton's numerical method and the Differential Evolution optimization strategy was applied to solve the material balance equations. The compositional data generated in this work are compared with the corresponding experimental data reported in the literature as well as the predictions of the CSMGem thermodynamic model.