A total of 5 phytoplankton samples from North Arabian Sea bordering Pakistan were collected just after Tasman Spirit oil spill and 16 samples after 1.5 year of spill during Bio-remedial Project. Marine centric diatoms were the targeted species in this study. Genus Rhizosolenia was found as the most diverse genus with 9 species which was followed by genus Chaetoceros with 7 species. Some genera were very rare represented by only one species. Light as well as Scanning Electron Microscopy has been used for identification of specimens. Moreover it has also been observed that species diversity was high in the samples collected after 1.5 year of the spill. Data was statistically analyzed and compared with the other reports from this area.
