Marine sediments are frequently contaminated by different organic and inorganic pollutants. Among the organic contaminants, polycyclic aromatic hydrocarbons (PAHs) are of considerable importance due to their carcinogenicity and toxicity. Aim of the present work is to compare PAH degradation efficiency, in sediment slurry aerobic batch tests on sediments from Cagliari (Italy) and El Kantaoui (Tunisia) harbours. Tests were performed with the addition of nutrients (biostimulation) or different bacterial strains (bioaugmentation) selected from sediments and seawater of the two harbours and able to grow on PAHs or to produce emulsifiers. The bioaugmentation was demonstrated to enhance PAH degradation as compared to biostimulation providing different efficiency on the two tested sediments.