Free‐radical chain addition to carbon‐carbon multiple bonds to form carbon‐hetero atom bonds is an important synthetic method of wide scope. Carbon‐halogen, carbon‐sulfur, carbon‐silicon, carbon‐germanium, carbon‐phosphorus, and carbon‐nitrogen bonds have been formed by this method, In this chapter, the mechanism, scope, limitations, and experimental conditions are treated for the addition reactions that lead to the formation of the six types of carbon‐hetero atom bonds mentioned above. Since the direction of addition of free radicals to carbon‐carbon multiple bonds is common to all classes reviewed here, it is briefly explained.