Chromium concentration was assessed in water and sediments of different habitats of Indus Delta mangroves. It is observed that highest concentration of chromium was 0.291 ppb in water and in sediments 72.20 ppm at Sandspit, whereas lowest concentration was 0.19 ppb in water and in sediments 18 ppm at Miani Hor, which is considered as comparatively pristine area. The higher levels of chromium is considered due to different anthropogenic activites including industrialization and urbanization. Mangrove sediments accumulate greater amounts of heavy metals like chromium than water or any other components of marine ecosystem and therefore, termed as biologeochemical sink. This characteristic of mangrove sediments is due to the high concentration of organic matter and sulphides under permanently reduced conditions.