Pharmaceutical counterfeiting is more and more a public health problem, especially in developing countries where the most counterfeit drugs are antibiotics, antimalarials and other life-saving drugs. The evaluation of the phenomenon extent is of great concern to the World Health Organization for carrying out a global strategy to combat the phenomenon. To this purpose, a reversed-phase liquid chromatographic method to perform the separation and simultaneous determination of three different kinds of antimalarial drugs (chloroquine, quinine and mefloquine) was developed. The method was validated by using both commercial and in-laboratory produced tablets and was then verified on various in-laboratory produced formulations differing in excipient composition. Finally, the method was successfully applied to the analysis of medicinal samples purchased from the informal market in Congo, Burundi and Angola.