High-resolution electron capture gas chromatography was used to determine residue levels of organochlorine pesticides in 13 commercially important fish species collected from the NW Arabian Gulf. While most of the residues were below the detection limit of 1 ~tg kg-1 wet weight, relatively low concentrations of ZDDT, endrin and dieldrin were detected in the edbile tissue of these fishes. The ZDDT residue levels ranged from 2 to 1 llig kg-1 wet weight, endrin ranged from none detected (rid) to 45 ~tg kg-1 and dieldrin from nd to 5 lig kg-1. A definite correlation was established between total organochlorine pesticide residues and lipid content (r = 0.6) for the NW Arabian Gulf fishes. Comparison with fish from Hor-al-Hammar Lake (an area that used to be sprayed with pesticides) has shown that the latter contained significantly higher residue levels. The ZDDT residue levels ranged from 5 to 45 lig kg-1 wet weight, endrin from 3 to 83 ~tg kg-~ and dieldrin from nd to 4 ~tg kg-1. Based upon the observation that the original DDT (p, p'-DDT) was identified in the NW Arabian Gulf fishes, it has been concluded that there was a recent input of DDT to this region. Since DDT application has been banned in Iraq, consequently it was assumed that DDT must originate from a more remote source.