The conventional kinetic treatment of the carrier theory of ion transport is subjected to a critical consideration. Elimination of an arbitrary assumption appears to lead not only to a better understanding of some phenomena but also to open the way to the formulation of a new type of competition. This type of competition is called “carrier competition” as opposed to “ion competition”, and is based on the assumption that the separate ion-carrier complexes may compete for the same enzymatic breakdown reaction. The implication of such a concept is that the carriers are chemically-related substances.