Oil pollution is a continual threat to all inshore marine habitats, and particularly pronounced in benthic animals. Therefore, the present study aims to elucidate the effect of the total dissolved/dispersed petroleum hydrocarbons (TDDPHs) on Cerastoderma glaucum (Bivalvia: Cardiidae) in Lake Timsah. Seasonal investigations were carried out at two sites during 2007. The TDDPHs were measured in soft tissues and shell of C. glaucum, water and sediment samples using spectrofluorometric analysis. Also, gas chromatographic analysis was carried out to detect the polyaromatic hydrocarbons (PAHs). Results revealed the TDDPHs content were high in male individuals than females, and were also more representative in the cockles' soft tissues than in its shells. Soft tissues of C. glaucum and sediment samples recorded significant differences during seasons and between the two sites. A negative correlation was found between TDDPHs content in soft tissues of C. glaucum and its age. The highest level of TDDPHs content in soft tissues (21.3 >g/g) was recorded at age of one year, while the lowest one (4.82 >g/g) was observed at age of five years. Concentration factor (CF) studied showed higher value in sediment during spring and in soft tissues during autumn. Gas chromatographic analysis (GC) clarified that PAHs accumulated in soft tissues were of high molecular weight (HMW) which represent hazard effect on marine organisms.