This study investigates the performance and economic benefits of applying inlet fogging in a heavy duty industrial gas turbine. To achieve the aim of the study, a heavy duty industrial gas turbine engine was modelled using a gas turbine performance software, GasTurb. The modelled engine was derived from the Frame 9E class of gas turbines. Consequent upon completing the engine modelling, ambient temperature profile data obtained from a location in Niger Delta region of Nigeria were used as input into the engine model to simulate its effect on the engine performance. Inlet fogging was simulated on the industrial gas turbine by inputting a water-to-air ratio of 0.4%, to cool and reduce the air inlet temperature by 10 degree Celsius. The simulation plots show that the gas turbine performance which dropped as a result of increased ambient temperature was enhanced by the application of inlet fogging. Economic analysis shows that approximately $2.4 million profit was recorded in one year when inlet fogging system was employed.