Present investigation was undertaken to know the levels of heavy metals (Mg, Fe, Mn, Cu, Ni, Zn, Cr, Pb, Co, Cd and Hg) in the brown algae Padina pavonia and P. tetrastromatica collected from three coastal areas of Karachi,.. The concentrations of Mg, Fe, Mn, Cu, Ni, Zn, Cr, Pb,Co, Cd and Hg in digested samples of seaweeds were measured by Atomic Absorption Spectrophotometer (Varian AA-20). Concentrations of Mg, Cd and Co were highest at Buleji; Cu and Ni at Paradise Point and Fe, Mn, Zn, Cr, Pb and Hg were high at Nathia Gali. In both species of Padina high concentrations of heavy metals are due to untreated wastes that are discharging from different sources such as industries and houses in coastal areas.