The chemistry of peroxide crosslinking was considered with the intention of the development of a fundamental kinetic model for the crosslinking process. The kinetics of the crosslinking of several elastomers by action of organic peroxides was studied, where dicumyl peroxide (DCP), t-butyl peroxide (TBP), and di(2-t-butylperoxy-isopropyl) benzene (DTBPIB) have been chosen as representative peroxides. The reaction mechanisms that have been proposed for the different steps in crosslinking chemistry were critically evaluated with the objective of developing a general description of the governing chemistry, where the mechanisms are consistent for all reaction steps in the crosslinking process. A fundamental kinetic model has been developed for the peroxide crosslinking, using population balance method that explicitly acknowledges the nature of the elastomer backbone and network, and thus reactants, intermediates and products with various reactivities. The kinetic model simulation was able to describe the complete crosslinking process including homolytic cleavage of the peroxide, beta cleavage of the oxy radical, hydrogen abstraction, addition reactions, radical coupling (crosslink formation), polymer scission and radical transfer for a wide range of compositions, and assortment of elastomers, using a single set of rate constants. POLYM. ENG. SCI., 49:60-72, 2009. (C) 2008 Society of Plastics Engineers