Abstract Highly crosslinked gels are used in high-permeability reservoirs to achieve good fluid-loss control during well completion and workover operations. Crosslinked gels are also commonly used for shutting off unwanted gas and/or water influx into production wells, and for improving the conformance of the near wellbore injection profile in naturally fractured or in high-permeability reservoirs. In all such applications, the appropriate design of the gel treatment is critical to ensure an efficient gel placement. One important variable of the gel application design is the rheology of the gel system for establishing the crosslinking kinetics and the gel strength after gelation is complete. Rheology of gels and gelation rates are commonly determined by rheological methods or in a qualitative mode through bottle testing using a well-known gel strength code (i.e., the Sydansk&s Code). The rheological measurements can be both time consuming and expensive, while bottle testing can lead to an inconsistent gel description as a result of the subjective nature of the gel strength code. This paper describes the use of low field nuclear magnetic resonance (NMR0 to monitor gelation rates and to characterize gel strength. This technique provides fast and accurate gel strength characterization and gelation monitoring. Through calibration with polymer concentration, crosslinker concentration, aging of gels, and the effect of brine, it is possible to predict NMR parameters. This then allows for a standardized method for the rheological categorization of gels. The results of this work present the correlation between the NMR spectra, rheological measurements, and the qualitative codification of gel strength.