Observations on oil slicks, tar residues and dissolved petroleum hydrocarbons (DPH) shortly after the oil spill resulting from the tanker accident in January 1993 showed negligible impact on the Indian EEZ of the Great Channel (Andaman Sea). DPH were between 0.31 and 1.85 mu g l sup(u-1) in the area examined. Tar residues were absent throughout the study area. Prevailing NE wind with resultant SW surface current appears to have pushed the oil patches out towards the open Indian Ocean. A follow-up survey of the same area was carried out in September-October 1993 and observations similar to those made during the earlier survey were recorded. The zooplankton biomass had increased considerably during the interval between the two surveys, but this was probably due to seasonal changes and natural variability. The spill did not cause any perceptible impact on the environment