Glycolysis is one of the extensively employed chemical depolymerization method for PUs (polyurethanes) waste and includes both rigid and flexible type products. The various steps involved in PU glycolysis are (1) grinding, (2) step-wise addition of waste to diethylene glycol in the presence of catalyst, (3) alkoxylation, and (4) degassing and filtration for recovering polyols. Dipropylene and tetraethylene derivatives showed good reactivity among the various polypropylene and polyethylene glycols. Increasing the number of OH groups in polyols reduces reaction rate of depolymerization. The cross-linked urethanes bonds were broken by using low molecular weight glycols in the presence of catalyst at elevated temperatures to produce polyols as major product, which further needs purification for its application. The purification method involves (1) single recovery method for the recovery of single product, whereas (2) double recovery involves the recovery of flexible and rigid polyols. Some microwave-based heating techniques can also be involved for the process modification. The resultant polyols can be used for making variety of products like PU monomer and adhesives with no or little loss to the desired physical properties. Hydrolysis with glycolysis techniques has compared well as an alternative depolymerization technique.