Taking advantage of the venue in Paris of the Third Mosasaur Meeting (May 2010), the mosasaur collections of the Muséum National d’Histoire Naturelle (MNHN) have been entirely checked and revised. The French holotypes have all been restored and most specimens kept at the MNHN have been placed in the Paleontology Gallery as part as a small exhibition organized especially for the meeting. The MNHN mosasaur collections include specimens from the 18th, 19th and 20th century from France, The Netherlands, Belgium, the United States of America, Morocco, Syria, Jordan, Egypt and Niger. Most of the mosasaur specimens discovered in France – including most holotypes – are kept in Paris. Besides the French types, the MNHN collections include several important historical specimens from abroad, the most famous being undoubtedly the Cuvier’s ‘Grand Animal Fossile des Carrières de Maestricht’, type specimen of Mosasaurus hoffmanniMantell, 1829, recognized as the first mosasaur to be named. This work aims to briefly present most of these specimens, with special focus on those found in France. The MNHN mosasaurid collections as a whole reflects the development of palaeontological researches in this Institution, from its foundation at the end of the 18th century up to the present time.