The purpose of this study was to establish regulatory trends related to competing drugs in several Latin American and Caribbean countries and to review regulations and national policies on generic drugs in these countries. Furthermore, information on the incentives to register and produce competing drugs, the promotion of international non-proprietary name (INN) use, the regulation of bioequivalence studies and the substitution of drugs prescribed by lower price alternatives to the public was also obtained. The results showed three regulatory categories: those countries that favour financing of competing drugs and the extended promotion of INN use, without restricting the substitution of innovative drugs with competitors; those that have a scheme oriented to the demonstration of the therapeutic equivalence, that is, countries that restrict the substitution of the original drugs to some authorised competing drugs; and those that are in an incipient stage of their regulation process. This variety causes difficulties in the characterisation of the pharmaceutical markets and can generate fictitious segmentations. In conclusion, harmonisation efforts should take into account the possible relationship among the definitions adopted by the countries, the national pharmaceutical markets development and their incentive policies for competition.