Abstract: This study focuses on the levels of heavy metals Cadmium (Cd) and Chromium (Cr) in seawater and selected bird Herring gull (Larus argentatus) tissues collected quarterly from selected field sites of coastal area of Hawksbay, Sandspit, and Korangi Creek, Karachi. All samples were examined using Atomic Absorption Spectrometer (Perkin Elmer. A. Analyst-700). Peak levels of Cd and Cr were found in seawater samples at Sandspit and Korangi Creek during 3rd and 4th quarter, respectively. While, minimum levels were detected at Korangi Creek and Hawksbay samples during 1st and 3rd quarter, respectively. Levels of Cd (18.758 ug/g) and Cr (18.77 ug/g) were elevated in kidney at Hawksbay and Korangi Creek during 2nd quarter. However, lowest value of Cr (0.66 ug/g) and Cd (2.767 ug/g) were in liver of Herring gull (Larus argentatus) at Korangi Creek during 4th and 1st quarter, respectively.