Polymer gel has been established as water-blocking agents in oil recovery application. In this practice, a mixture known as gelant is injected into target area and set into a semisolid gel after a certain adequate time. Besides profile modification and water shutoff, the role of the polymer gel in conformance control is to block high permeability regions, before diverting injected water from high permeability to low permeability zones of the reservoir. It is to boost the oil displacement and sweep efficiency. This is the key to improve oil recovery in the heterogeneous oil reservoirs. However, very limited gels are applicable for harsh conditions, especially in high-temperature reservoirs. Organically cross-linked polymer is 1 of the materials for conformance control at high-temperature reservoirs. Many experimental works and field applications have exhibited the potential of this technology. This paper presents a concise review on this polymer gel for conformance control at high-temperature wells. Firstly, in situ organically cross-linked polymer gel has been introduced, and the reason of the use over other types of polymer gels is summarized. The early studies of organically cross-linked gel systems are also discussed, followed by the chemistry and the gelation mechanisms. An extensive review on factors that affect gelation kinetics and field applications is also discussed in some detail. © 2018 John Wiley & Sons, Ltd.