Oil companies are considered to be a source of chronic pollution with continual discharge of wastewaters into the environment. Thus, the impact of petroleum contamination from French-Tunisian Oil Company on the endorheic basin Sabkhat Boujemal is assessed. This area is a continental depression that has no relation with the sea; instead this basin is just an evaporative system. The results show that aliphatic n-alkanes and polycyclic aromatic hydrocarbons (PAH) concentrations, measured on surficial (0-4 cm) sandy sediments, range from 705 to 4560 mg/kg -1 dry sediment and from 11 to 1124 mg Kg -1 dry sediment, respectively. The spatial distribution of these concentrations shows high levels in the vicinity of the oiled water discharge. The distribution pattern of n-alkanes with no odd or even dominance, high levels of unresolved complex mixture (UCM) (198.1-1500 μg/g-1 dry sediment), associated to the combination of different evaluation indices enhance this assessment. Indeed, levels close to 1 for both carbon preference index (CPI) and low molecular weight to high molecular weight ratios (≤C24:>C24) as well as values of n-alkanes/C16 <50 and pristane/phytane close to 1 suggests the presence of petroleum hydrocarbon inputs from the effluents rejected by the French Tunisian oil company in the Sabkhat. To elucidate sources of PAHs, three molecular indices (phenanthrene (Phen)/anthracene (Ant), fluranthene (Flu)/pyrene (Pyr), and Σmethyl phenanthrenes/phenanthrene) are used. As Ant, Flu, and alkylated PAH are respectively less thermodynamically stable than Phen, Pyr and unsubstituted PAH homologues, ratios of Phen/Ant <1, Flt/Pyr >10, and ΣMethyl Phen/Phen >2 indicate petrogenic origin of PAH. Conversely, ratios of Phen/Ant >1, Flt/Pyr <10, and ΣMethyl Phen/Phen <2 are characteristics of pyrogenic PAH. The results show intermediate values of PAH indices, which indicate a mixture of pyrogenic and petrogenic origins. [ABSTRACT FROM AUTHOR]