This paper reviews developments in the field of utilization of poly(ethylene terephthalate) [PET] scrap for the manufacturing of unsaturated polyester resins [UPR]s. Sources of PET scrap are presented. Different processes of manufacturing of UPRs are compared. Partial glycolysis as the first stage of synthesis of unsaturated polyesters [UP]s using PET scrap is discussed. Influence of the PET segment length in UP molecules on the rheological properties of UPRs is described. Properties of cured UPRs obtained from PET as well as their fields of application are given.