Gas turbines are used extensively for aircraft propulsion, land-based power generation, and industrial applications. They are consist of many parts. One of the important parts is the blade and disc. Blade and disc are individual components that make up the compressor section. That is why all effects on these components directly affect the unit itself. For that reason engineering calculations on such critical parts are important. Some power plants and gas turbines failed regarding wrong engineering calculations. One of them happened two years ago on GE (General Electric) 9FB gas turbine in Turkey. Some turbine blades have broken and created high-cost damage on the unit. Some engineering calculations have been failed regarding side running conditions. For that reason, this study has been performed to protect and verify the engineering value of AEN 94.3A F-type gas turbine side running conditions. In this study, the structural and thermal analysis of the final stage compressor rotor blade and disc, which are currently used on-site, was performed by using the ANSYS program. Initially, basic knowledge of blade and disc design drawings were reviewed and design steps of the existing 3D (Three dimensions) blade and disc configuration were described. For that reason, a 3D model of the existing compressor blade and the disc has been done in the SolidWorks design program. Later on, this model was transferred to the ANSYS program and analyzed. In the analysis, the parameters formed in the blade geometry were determined. By creating a design geometry with the selected parameters, the stress of the existing blade under operating conditions was examined. All external parameters in this study were taken from an F-type gas turbine operation under real field conditions. The stresses obtained from different regions on the blade were examined. After the thermal and structural analysis, obtained results have been compared with side engineering measurements. By comparison, it was observed and verified that the unit normal side running condition is safe and engineering calculations are sufficient.In this study before starting the analysis, general information about gas turbines has been presented. Gas turbines have been briefly introduced and then, the basic operation principles of turbines have been explained. As it is known, gas turbines are shaped based on thermodynamic principles. In this study, engineering thermodynamics in gas turbines is briefly explained as well.