© 2022, Gazi Universitesi. All rights reserved.Polyethylene terephthalate (PET) bottles which are thermoplastic materials are used very commonly for the storage and transport of carbonated beverages. The most used production method for PET bottles is the Injection Stretch Blow Molding (ISBM) process. There is a variety of parameters affecting the produced PET bottles’ performances. Amongst these parameters, stretch rod movement, blowing pressure and preform surface temperature are the most important ones. Assignation of the optimal design parameters in PET bottles is taken into account. The effects of the parameters such as Preform Temperature (°C), Stretch Rod Position (mm) and Final Pressure (Bar) were analysed with the Taguchi method (TM), Grey relational analysis (GRA) and ECHIP. Body-weight (gr) (R1), Top Load (Pa) (R2), Burst Pressure (Bar) (R3), Stress Crack Resistance (Min.) (R4) and Tg (oC) (R5) were consiedered as performance parameters. The experimental design proposed by Taguchi involves using orthogonal arrays. An L9 orthogonal array was chosen for the procedure. Primarily, the performance parameters were optimized with the ECHIP Design of the Experiment (DOE). Thereafter, all of the factors were optimized together with TM, GRA and ECHIP.