This investigation represents the extensive study of the spatial distribution and sources of hydrocarbons in the Gulf of Tunis. Sediments and fish were sampled within the open sea of the Gulf of Tunis during August 2004. All samples were extracted with organic solvents, separated by silica/alumina column chromatography, and analyzed by spectrofluorometry for the determination of total aromatic hydrocarbons (TAH) and gas chromatography coupled with flame ionisation detector (GC-FID) for the determination of aliphatic hydrocarbons (AH) and polycyclic aromatic hydrocarbons (PAHs). Analysis of AH and PAH was confirmed with gas chromatography coupled with mass spectrometry (GC-MS). Sediments and fish samples have variable concentrations of TAH ranging from 0.8 to 9 μg g-1 and from 0.1 μg g-1 to 0.8 μg g-1 in tissues, respectively. The highest hydrocarbons levels (0.1 to 1.6 μg g-1) were found in liver in all fish species. Concentrations of sum AH and PAH in tissue of different fish species varied, respectively, from 0.28 to 1.05 μg g-1 dry weight and from 0.1 to 0.35 μg g-1 dry weight, respectively. In sediment concentrations of sum AH and PAH varied between 0.04 and 2.94 μg g-1 dry weight and between 0.01 and 2.6 μg g-1 dry weight, respectively. © 2010 Institut National des Sciences et Technologies de la Mer (INSTM).