Abstract: The fresh water gastropod Lanistes carinatus was tested to be used as potential biomonitor for the trace metals, Copper, Cadmium and Lead. Some chemical and biological measurements were sampled and measured in two consecutive years 2005 and 2006 in different stations from Damietta Branch of Nile River. Cu level in water not detected in all investigated sites, while concentrations of Cd and Pb in water and the concentrations of Cu, Cd and Pb in sediment varied in different stations. It was found, metals concentrations were higher in sediment than those of water because sediments are important sinks for various pollutants like pesticides and heavy metals. The levels found for determined metals in water and sediment in the area are below of the permissible limits that set by the United States Environmental Protection Agency (EPA) except some deviations in managements of water especially at Kafr Saad. Concentrations of these metals in soft tissues of gastropod Lanistes carinatus were higher than those of sediment and vary widely in different sites suggesting that this gastropod accumulate these metals and consequently would be of use for monitoring. The population density of Lanistes carinatus decreased sharply opposite to discharge point of Electric Plant of Talkha and Kafr Saad. This may be due to thermal pollution of the plant. The study suggested the use of Lanistes carinatus as Cu, Cd and Pb biomonitor in nature and also recommended a construction of closed cycle for cooling water of the power stations to prevent heated water from being discharged into the River and also controlling the discharge of wastes and industrial effluents into Nile.