Polymer flooding is the most successful EOR method consisting in increasing the viscosity of the aqueous phase injected in a reservoir to improve its efficiency to sweep the oil to producer wells. EOR polymers are high molecular weight partially hydrolyzed polyacrylamides. The degree of hydrolysis and the polymer chemistry must be selected carefully according to the brine composition to avoid any incompatibilities and prevent from precipitation with divalent cations. The residence time of the polymer solution in the reservoir can range from several weeks to several months or even years, especially offshore. During this lapse of time, and upon the action of the temperature of the reservoir, acrylamides moieties can hydrolyze into acrylates increasing the degree of hydrolysis of the polymer and the risk of precipitation with the divalent cations. In the literature, the only official protocol is the one given by the American Petroleum Institute. This technique recommends the use of several cycles of vacuum and nitrogen flushes with frozen and unfrozen of the polymer solution to decrease the concentration of dissolved oxygen below 100 ppb. The ampoules are then sealed under vacuum using a blue torch. The quality of the sealing and of the deoxygenation is strongly operator dependent and oxygen ingress can be observed through micro cracks during the melting and cooling of the glass seal. In the field, polymer solutions are generally prepared under Nitrogen blanketing and remaining oxygen in solution is rapidly striped out by the reservoir acting as a strong reducing agent. Therefore, O2 concentration is lower than 5 ppb. To reproduce such level of dissolved oxygen, the use of a glove box has been progressively generalized to the main laboratories. Results remain however quite variables depending on the protocol that has been followed. To align procedures so that to generate more homogeneous results, this paper presents the most appropriate practices developed upon the last decade. It is based on deep analysis of failures and successes in conducting thermal stability tests. The aim is to bring experimental inputs to draw new guidelines for the thermal stability evaluation of EOR polymers. The following items have been considered: - Preparation of a polymer solution for thermal stability; - Selection of the most appropriate material to be used for aging, for instance type of containers (glass versus stainless steel), types of plugs