CFD predictions of emissions using conventional RANS methods have been shown to be inaccurate, sometimes by orders of magnitude. In recent years, deeper details of the chemistry-aerodynamics coupling in lean-premixed combustion regimes have been demanded from CFD predictions. Large Eddy Simulation (LES) of non-reacting flows provides high-fidelity predictions of flow field aerodynamics in gas turbine combustor chambers, critical for accurate emissions predictions. While LES has been validated for many simple lab combustors, there are few simulations that have used this method for practical industrial combustors at their baseload conditions. This thesis describes its application to an industrial gas turbine combustor at elevated pressures and temperatures. A well-validated commercial code, Fluent 6.3, has been used to obtain reacting and non-reacting flows that occur in this combustor geometry. The final emissions predictions were compared with rig test results.