During the period of february/97 to november/98 and may/99 to december of the same year were investigated monthly the levels of total aromatic hydrocarbons (TAH) in samples of marine sediments collected in the bay of Tumaco.The detected concentrations on the area were smaller or equal to 2.072 ug/g; it was during the time in which there was not any event related with spills or arrival of crude oil for action of the oceanic dynamic.Otherwise they reached up until the 3.696 ug/g.In this way, the obtained information becomes a technical tool for evaluation of the levels of these toxic substances in the marine sediments of the area.Just as it could be observed in the obtained concentrations in the tater taken samplings to the spilled of crude oil in Emeraldas-Ecuador, wich were very closely to 3.9 ug/g, defined by the NOAA as "high concentration" for sediments.