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Due to its significant position between the Sahara Desert and tropical Africa, Senegal may have played a decisive role in the dispersal of modern humans between North and sub-Saharan Africa. However, our knowledge about these intra-African dispersals and the character of the demographic connection between North and sub-Saharan Africa are poorly understood and archaeological records in the Sahel are limited. Between 1940 and 1960, the Senegalese littoral yielded prehistoric sites attributed to the Middle Stone Age (MSA) or Middle Palaeolithic. This chrono-cultural framework is based on typological considerations about lithic industries generally found in secondary or disturbed stratigraphic contexts. Of these sites, Tiemassas has been considered to be the most important. Located about 100 km from Dakar, the site has been considered Middle Palaeolithic, Mesolithic and even Neolithic, but has not been analysed in detail. In this paper, the compositions of the lithic assemblages represented at Tiemassas are discussed and their technological strategies are analyzed. Results indicate that the site is characterized by the use of diverse strategies of raw material exploitation in relation to the morphology and morphometry of the exploited pebbles. The assemblage is flake dominated, generally characterized by typical MSA methods such as Levallois, opportunistic (Systeme par Surface de Debitage Alterne (SSDA)) and discoid flaking, and more rarely by laminar methods. Finally, retouch is usually applied to transform objects into side-scrapers. These results are indicative of a MSA cultural attribution and represent a first step in the process of definition and description of the Senegalese MSA together with its wider continental context. (C) 2015 Elsevier Ltd and INQUA. All rights reserved.