This review assesses the challenges facing the development of catalysts for the amination of alkenes. Short sections are included summarizing the use of both ammonium ion and amide ion as catalysts. The principal transition metal systems that have been used as homogeneous catalysts are discussed in terms of their mechanistic features. The use of organolanthanide complexes as amination catalysts is also discussed in terms of their reaction mechanism. The review also includes enzymic amination catalysts and the use of mercury photosensitization for alkene amination via hydrogen atom abstraction. A section covering allylic amination is also included.