Coastal waters have been widely used by the littoral countries of the Middle East for siting desalination and power plants to take advantage of the availability of unpolluted sea water for establishing cost effective feed intake and once through cooling system. Huge quantities of raw seawater are being withdrawn from the sea for the unimpeded production of freshwater, greatly needed in the region. The effect of marine environment has been found to ramify over the plants, principally as biofouling of intake structures, pumps, seawater piping system, heat exchangers, etc. Despite widespread occurrence, not much information is available on the instances of biofouling encountered in desalination and power plants. The study was aimed at understanding the nature of biofilm formation and its further development on materials exposed to sea water, the composition of biofouling communities in space and time, the succession of flora and fauna in a biofouling environment and the principal ecological factors having a bearing on the phenomenon. Five experiments were carried out over a period of two S,ears representing different seasons. Glass slides, were suspended in the sea on a Diatometer and kept afloat with buoys so that the slides remained constantly submerged in water. The slides, retrieved at pre-determined intervals, were subjected to detailed examination, and the data collected on the parameters mentioned above constitute the subject of this paper. Biofilm showed a growth in thickness for the first three weeks followed by a reduction attributable to sloughing of the biofilm. The biofouling community was composed of 31 groups of organisms which exhibited a widely varying pattern of incidence, abundance and succession. The settlement of organisms increased with increased exposure time. Environmental factors such as temperature, conductivity, total suspended solids, and dissolved oxygen have been examined in the context of biofouling activity in the sea. The paper discusses the diverse aspects of biofouling within the ecological frame of a coastal intake bay.