Our work is part of an oil exploration effort in the offshore area of the central part of the Mauritanian coastal basin, which is part of a series of passive-margin basins with Mesozoic and Tertiary sedimentation. This study aims to characterize the Cretaceous source rocks. Two boreholes were selected in this study area and subjected to geochemical analysis using the Rock-Eval-6 pyrolysis method. The results showed that these source rocks contain predominantly marine organic matter (Type II). Type III (continental) organic matter is very rare. Consequently, these Cretaceous source rocks exhibit moderately good petroleum potential. The maximum temperatures (T°max) recorded indicate that these source rocks are located in immature to marginally mature zones.