The goal of this investigation is to obtain alkyd resins using recycled poly (ethylene terephthalate), PET, and different vegetable oils. Glycolysis of PET waste using pentaerytheritol (PEr) was used to produce suitable hydroxyl oligomers, GPEr, for alkyd resin. The glycolysis was carried out in the presence of manganese acetate as a catalyst and m-cresol as a solvent at 220 °C. Alkyd resins were prepared using phthalic anhydride, PET waste, glycerin, sunflower oil or linseed oil and ethylene glycol to produce PET-based alkyd resin. GPEr was used instead of PRT waste to produce the second type of alkyd resin based on GPEr. The reactions were carried out in the presence of butylhydroxytin oxide as a catalyst to prepare alkyd resins. The curing characteristics of the resins produced were investigated. Corrosion resistivity based on salt spray and cathodic disbondment were evaluated for the cured alkyd as organic coating for carbon steel.