The anthropogenic marine debris in the Mediterranean Sea represents a growing concern because of its potentially harmful impact on marine ecosystems. In this paper, we investigated the composition of marine debris in the Iskenderun Bay seafloor. Between November 2009 and April 2010, a total of 34 trawl operations were conducted. Hauls lasted 60–385 min, and the towing speed varied between 2.7 and 2.8 knots. The estimated average marine litter concentration was 450.94 item/km2 (90.34 kg/km2). Plastic was the dominant material type (87%) at all stations. Single-use plastic items represented about 74.9% of the total marine litter. Our results showed that there is severe plastic pollution on the seafloor of Iskenderun Bay that may cause significant damage to both the fisheries sector and the marine environment.