The results from several research cruises, covering the period of 1969 to 1982, indicate that the spatial distribution of pelagic tar (tar balls) is highly heterogenous. However, the Ionian Sea had a considerably greater accumulation than the other regions.The closing and reopening of the Suez Canal had little influence on the overall quantity of pelagic tar. The general trend does indicate that the quantity of this pollutant has been decreasing since 1975.