A study on the benthic meiofaunal density of Pitchavaram mangrove, along with environmental variables like temperature, salinity, dissolved oxygen, organic carbon and sediment characteristics was made during September 2000 to August 2001. The monthly variation was pronounced for the different taxa with peak abundance in June (summer) and minimum in November and December (monsoon). The meiofaunal density was highest in sediments with Avicennia cover (44-7275 No./10m2) followed by Rhizophova cover (152-4400 No./lOcmZ). The taxa with no mangrove cover recorded the lowest density (109-1198 No. /10cm²). Meiofauna was represented by nematodes, copepods, kinorhynchs, foraminiferans, oligochaetes, polychaetes, ostracods, turbellarians and allogromiids of which nematodes were the most dominant (9-99%). The mangrove regions harbour a very high density of meiofauna though not very diverse. The plant cover may have some impact on the meiofaunal population densities present in the substrate, and further studies needs to be undertaken to determine the cause for maximum abundance observed in sediments with Avicennia cover compared to Rhizophora.