The Bivalve carpet shell clams Donax semistriatus was collected seasonally from three locations on the Mediterranean coastline, Idku urban, North Egypt. The greatest dominant size of the clam D. semistriatus is the individuals with class intervals of 12.8-22.3 mm. The population of D. semistriatus exhibited two periods of recruitment each year. The results of the biochemical analyses exhibited a significant increase in moisture contents in D. semistriatus during the summer season. The obvious increment in protein contents was reported in D. semistriatus during the autumn season, while ash contents decreased during the winter season. Both aliphatic and aromatic hydrocarbon concentrations were higher in winter than in summer. The present Highest content of aliphatic hydrocarbon (48605.87) was in summer at site "2" and the lowest content of aliphatic hydrocarbon (4052.33) was in winter at the site "1". The highest content of aromatic hydrocarbon (4525.56) was in winter at site "3" and the lowest content of aromatic hydrocarbon (873.36) was in summer at the site "1". Site "2" has the highest concentration of hydrocarbon because of sea currents near the natural gas company, located in site "1".